È meglio avere meno bisogni che possedere più cose (R.A. n. 18)
La povertà evangelica nella tradizione dei Servi

Franco M. Azzalli, OSM

Premessa

Vi chiedo di permettermi di iniziare con una breve premessa, che considero metodologicamente importante per affrontare il tema della povertà evangelica.
Recentemente ho avuto la grazia di accompagnare in Israele fra Carlos M. Razo Villanueva, il primo Servo di Maria che costituirà la nuova comunità in Terra Santa nel santuario di “Nostra Signora della Palestina” a Beth Shemesh.
Nei giorni nei quali siamo stati ospiti del Patriarcato Latino di Gerusalemme (che ci ha invitati a custodire l’unico santuario mariano della Terra Santa) abbiamo avuto anche la possibilità di visitare alcuni dei luoghi santi di Gerusalemme.
Il luogo che forse più ha colpito il mio cuore è il “buco” dove è stata piantata la croce, il luogo dove Cristo è morto. Vedendo quel “buco”, immaginando l’incomprensione e il non riconoscimento da parte della folla che stava a guardare, ho riconosciuto come sia una cosa terribile e grande il male, se Dio ha dovuto accettare un sacrifico tale, una morte del genere. Inoltre, di fronte alla concretezza di quei luoghi, ho visto come non sia possibile tornare a casa con il dubbio che il cristianesimo sia una favola.

Il giorno dopo il ritorno, mercoledì 4, sono andato alla congregazione per gli Istituti di Vita Consacrata e le Società di Vita Apostolica (prima detta “congregazione per i religiosi”) a richiedere alcuni documenti. Quella mattina ho fatto una duplice esperienza.
Innanzitutto, sono stato colpito da quello che vedevo. Era mercoledì e c’era un grande via vai di gente per l’Udienza generale del Papa – ed era ancora appeso l’arazzo per la beatificazione di Giovanni Paolo II. Quello che avevo davanti agli occhi era la perfetta continuità di ciò che avevo vissuto nei giorni precedenti: la Chiesa che sto vivendo è la continuità fisica della presenza di quell’Uomo del Calvario, che ha dato la vita per me e si rende presente attraverso i Suoi (Dove due o tre sono riuniti nel Mio nome, Io sono con loro).
Ma non è finita. Mentre attendevo davanti a un ufficio, mi è venuto alla mente che solo ventiquattro ore prima ero di fronte al “buco” del Calvario, drammatico segno del fatto che Cristo ha dato la vita PER ME. E improvvisamente – per quei momenti di grazia e di memoria che ogni tanto accadono – ho avuto ben chiaro che anche attendendo i documenti stavo davanti a quel “buco”: era la stessa cosa, l’istante che vivevo aveva la stessa dignità, perché la dignità di quell’istante non era data da ciò che stavo facendo, ma dal fatto che Lui sta dando la vita per me ORA.

Perché questa premessa?
Ritengo che approfondire il tema della povertà evangelica possa portare frutto per noi solamente se la memoria di Cristo riempie il nostro cuore, se cioè paragoniamo continuamente quello che il nostro cuore nel profondo desidera con quello che ci accade davanti agli occhi. Anche paragonarsi con i testi e i personaggi della nostra tradizione può essere fatto solo in questa dinamica di memoria di Cristo e ascolto del desiderio profondo del nostro cuore: altrimenti quello che sentiamo e vediamo sarà qualcosa di esterno a noi, non unito nella nostra vita.
Se registriamo la reazione profonda avuta di fronte al titolo di questa riflessione, avremo un primo test di quello che desidero dire.
Ma la memoria di Cristo (ed è la seconda parte dell’esperienza che ho vissuto) è presente nella Chiesa, fino al “capillare” ultimo che è la nostra comunità, proprio quella in cui viviamo ora. Senza questo legame, tutto ciò che ci diciamo resta un discorso, magari anche bello, ma che non tocca la nostra vita, provocandola.

Desidero affrontare il tema – per brevi accenni – attraverso i seguenti punti :
1. Regola di sant’Agostino
2. Alle origini dei Servi
3. La Lettera spirituale di fra Angelo Maria Montorsoli
4. Le nostre Costituzioni
5. Le Linee ispiratrici del Capitolo generale 2007

1. Regola di sant’Agostino

Voglio evidenziare questi tre aspetti della povertà evangelica che mi pare emergano dalla Regola di sant’Agostino.

a) La Regola di sant’Agostino, dopo la premessa essenziale che descrive la ragione della nostra vita:

Fratelli carissimi, si ami anzitutto Dio e quindi il prossimo, perché sono questi i precetti che ci vennero dati come fondamentali (n. 1)

inizia subito a trattare il tema della povertà.
Infatti nel primo capitolo, intitolato “Scopo e fondamento della vita comune” Agostino descrive nell’articolo 3 lo scopo della vita comune:

Il motivo essenziale per cui vi siete insieme riuniti è che viviate unanimi nella casa e abbiate una sola anima e un sol cuore protesi verso Dio (n. 3).

E senza frapporre nulla, prosegue:

Non dite di nulla: “È mio”, ma tutto sia comune fra voi. Il superiore distribuisca a ciascuno di voi il vitto e il vestiario; non però a tutti ugualmente, perché non avete tutti la medesima salute, ma ad ognuno secondo le sue necessità. Infatti così leggete negli Atti dagli Apostoli: “Essi avevano tutto in comune e si distribuiva a ciascuno secondo le sue necessità”. […] (n. 4).

Il fondamento della vita comune viene individuato chiaramente nella povertà evangelica: essa è la prima delle “vie” per vivere l’unità tra di noi. E quindi, all’opposto, il non vivere la povertà evangelica è un grave ostacolo alla unità della comunità.

Dopo aver concretizzato con esempi estremamente chiari (e anche attuali) il legislatore termina riprendendo il tema dell’unità:

Tutti dunque vivete unanimi e concordi e, in voi, onorate reciprocamente Dio di cui siete fatti tempio. (n. 9).

b) Al numero 31 della Regola troviamo inoltre un suggerimento che le nostre Costituzioni, come vedremo, hanno ripreso:

Nessuno mai lavori per se stesso ma tutti i vostri lavori tendano al bene comune e con maggior impegno e più fervida alacrità che se ciascuno li facesse per sé. Infatti, la carità di cui è scritto che non “cerca il proprio tornaconto”, va intesa nel senso che antepone le cose comuni alle proprie, non le proprie alle comuni. Per cui vi accorgerete di aver tanto più progredito nella perfezione quanto più avrete curato il bene comune anteponendolo al vostro. E così su tutte le cose di cui si serve la passeggerà necessità, si eleverà l’unica che permane: la carità. (n. 31).

È interessante anche che qui Agostino collega la pratica della povertà evangelica alla esperienza della carità, cioè in questo caso, al bene della comunità per poter meglio tendere ad essere segno di unità.

c) Ultima citazione dalla Regola del santo Dottore di Ippona è la famosa frase tratta da Seneca. Parlando dei malati, Agostino scrive:

[…] Ma appena si siano ristabiliti, tornino alla loro vita normale, che è certamente più felice, poiché è tanto più consona ai servi di Dio quanto meno è esigente. Ormai guariti, il piacere non li trattenga in quella vita comoda a cui li avevano sollevati le esigenze della malattia. Si considerino anzi più ricchi se saranno più forti nel sopportare la frugalità, perché è meglio aver meno bisogni che possedere più cose.

È l’affermazione della povertà come essenzialità di vita, libertà dai bisogni. Quanto attuale questo richiamo! Nella Lettera Frate Alessio, uno dei Sette, che il Priore generale ha in-dirizzato all’Ordine in occasione dei settecento anni della morte dell’ultimo dei Fondatori, leggiamo:

La figura di Alessio ci è riproposta anche per quella che definirei la non ricerca del privilegio “dovuto” (per anzianità, per autorità o anche autorevolezza) attraverso una “diversità” che è a volte affermazione sterile di sé. […] Questa semplicità e sobrietà di vita è certamente un valore che va controcorrente rispetto alla mentalità di oggi, della quale anche noi siamo imbevuti: ma ritengo debba essere decisamente recuperato per una serenità di vocazione e anche di testimonianza personale e comunitaria. (n. 13).

Possiamo avviare una riflessione sui tre punti che sono emersi:
a) povertà evangelica come fondamento della vita comune
b) legame della povertà evangelica con la carità
c) povertà evangelica come essenzialità di vita, libertà dai bisogni.

Mi pare importante paragonare queste affermazioni di Agostino, che vengono dalla sua esperienza personale e da una profonda conoscenza dell’animo umano, con la nostra esperienza personale. Chiediamoci:
- Queste affermazioni corrispondono alla realizzazione vera di me?
- Oppure sento queste frasi come esterne a me, forzate, imposte?
- Quali sono le vere esigenze del mio cuore?
Ricordando, come scriveva Paul Verlaine, che l’uomo trova quello che cerca; e noi troviamo l’infinito proprio perché lo cerchiamo, il cuore di ogni uomo lo cerca .
Credo che le tre priorità del Capitolo generale 2001 siano ancora attuali, ricordando in particolare che la ricerca di Dio è fondamento di tutta la nostra vita.
Anche in questa riflessione ci viene in aiuto la parola di p. Àngel nella citata Lettera Frate Alessio, uno dei Sette:

Ritengo infatti che se non siamo disponibili e persuasi a comprendere tutto ciò che la nostra vocazione implica – fino alle conseguenze più concrete – i sacrifici che essa ci fa fare possono sembrare obiezioni, mentre semplicemente sono descrizioni di una strada, condizioni di un cammino. Questo è una grande lezione della vita di frate Alessio. (n. 14).

2. Alle origini dei Servi

Anche qui farò solo alcuni accenni, attingendo dal ricco patrimonio dei testi delle nostre origini. L’esperienza originale, rimane comunque normativa, pur nel continuo tentativo di adattarla ai tempi che si vivono per conservare l’intuizione carismatica iniziale.

a) L’esperienza dei primi Sette

I. Desidero evidenziare solo tre aspetti del cammino dei nostri primi Padri nel sentiero della povertà evangelica come lo conosciamo dalla Legenda de origine Ordinis.

1. Il primo gesto che i nostri Sette padri, ancora nella vita laicale, compiono per prepararsi a rispondere alla nuova chiamata del Signore è il gesto evangelico del distacco dai beni della terra e del dono ai bisognosi, senza dimenticare i propri cari. La Legenda de origine (LO) al n. 30 afferma infatti:

Perciò si sciolsero prima di tutto da ogni legame per poter attuare liberamente e secondo giustizia l’unione desiderata. Disposero quindi delle loro case e delle loro famiglie: a queste lasciarono il necessario, il resto lo distribuirono ai poveri e alle chiese per il bene delle loro anime, stabilendo di non conservare per sé assolutamente niente al momento della loro unione.

E la Legenda sottolinea il fatto che questa decisione, presa in vista della vita insieme, era stata

una decisione non presa alla leggera e come per caso, ma con matura e salda deliberazione, sotto l’impulso speciale della Nostra Signora.

2. L’abitazione dove vivono è descritta a Firenze come una piccola casa (n. 31) e poi a Monte Senario una povera dimora (n. 44). Ma quanta vita lieta in quella dimora! Dal Pino scriveva anni fa: «Eppure questa umile abitazione […] è descritta con tale freschezza da apparire, come deve essere stata, spiritualmente gioconda ad abitarsi».

3. A Monte Senario, quando si descrivono le tre “tende”, a proposito di quella “mistica” si afferma:

La tenda mistica, poi, fu il particolare rifugio che vi trovarono i frati del nostro Ordine: rifugio costruito soprattutto dalla Nostra Signora, fondato sull’umiltà dei nostri padri, costruito con la loro concordia, conservato dalla povertà, abbellito dalla purezza. La presenza di frati santi, che si avvicenderanno fino al giorno del giudizio, è la sua perfezione (n. 44).

La povertà evangelica abbracciata dai Sette è quindi una condizione, un mezzo, estremamente significativo per rispondere alla chiamata della Nostra Signora ed edificare con Lei il Suo Ordine nel mondo.

II. La documentazione archivistica ci conferma questa scelta dei primi Padri. Tutti conosciamo il così detto Atto di povertà del 7 ottobre 1251. Si legge nell’atto notarile:

[…] Radunati frate Figliolo [o Bonfiglio] priore della chiesa di Santa Maria di Monte Sonaio e i sottoscritti frati presso il loro luogo [convento] posto vicino a Firenze in località detta Cafaggio, cioè frate Alessio, Ricovero, Benigno, Vigore, Bonaventura, Ruggero, Giovanni, Clemente, Bartolo, Albertino, Nicolò, Egidio, Cambio, Matteo, Bonagiunta, Ildebrandino, Benedetto, Iacopo e Manetto, […] promisero e fecero voto a Dio onnipotente e alla beata Maria che mai, direttamente o tramite il loro priore o custode […] o qualunque altra persona, avrebbero posseduto o fatto possedere a proprio vantaggio beni immobili di qualunque specie siano

e se qualche bene immobile venisse loro donato

sia subito e immediatamente del signor Papa e della sacrosanta Chiesa romana. In tale modo però che il signor Vescovo nella cui diocesi fossero collocate le cose donate, ne abbia totale e piena giurisdizione e a lui appartengano i frutti e gli utili […] e di questa possa il predetto Vescovo disporre […] per la salvezza e l’espiazione dell’anima dell’offerente e per farne elemosina ai frati dell’Ordine o del convento predetto, ma solo in tempo di necessità, come a lui [Vescovo] meglio parrà.

Al di là delle interpretazioni del documento e del suo utilizzo, rimane il fatto che questi primissimi Servi di Maria compiono liberamente questa scelta per affermare la propria vocazione.
«In seguito – scriveva dal Pino – quando per motivi vari la povertà collettiva istituzionale dovrà essere abbandonata prima di fatto e poi anche di diritto, non mancheranno attestazioni, sino al termine del secolo XIII e oltre, di una vita comunitaria caratterizzata dalla modestia e dalla semplicità dei costumi. I Vescovi inviteranno i loro fedeli a sovvenire alle necessità più immediate dei poveri frati, con espressioni così vive da evadere quelle del formulario consueto». Si conosce ad esempio il caso di Foligno, dove il Vescovo il 19 febbraio 1276 concesse la remissione di quaranta giorni di indulgenza ai fedeli che avessero aiutato i nostri frati i quali erano «ridotti a tale stato di povertà, da non poter rimanere nel sopraddetto luogo senza l’aiuto di altri».

III. Non si può infine, parlando delle origini, dimenticare la luminosa testimonianza di frate Alessio, l’ultimo dei Sette. Tutto il capitolo quinto della Legenda de origine è di perenne edificazione e richiamo alla nostra vita.

a) L’esperienza di Filippo Benizi

Tutta la vita di Filippo Benizi è testimonianza di povertà evangelica. L’episodio del miracolo ad Arezzo ci ricorda come a Filippo, povero, non restasse che rivolgersi a Dio mediante la Vergine per ottenere che i suoi frati non muoiano di fame:

Un giorno i frati avevano saltato l’ora del pranzo, e il beato Filippo li confortò come poteva. Intanto, entrato in chiesa, salutò la beata Vergine, pregandola e supplicandola di non lasciar morire di fame i suoi Servi, lei che era madre pietosa. E mentre stava così in orazione, improvvisamente bussarono alla porta del convento. Un frate andò subito ad aprire e non trovò nessuno, ma solo due ceste piene di pane bianchissimo, che prese e portò davanti ai frati; e si affrettarono alla mensa per mangiarlo: e così insieme col beato Filippo furono prodigiosamente rifocillati. E in seguito ebbero sempre in abbondanza il pane e altre cose, per i meriti del beato Filippo (LP vulgata, n. 14).

Che bella testimonianza di povertà evangelica legata alla fede: un uomo per il quale la sola ricchezza è Dio.

Come conclusione del nostro sguardo “a volo di uccello” sulle nostre origini, vale la pena citare un passo molto bello dell’ultimo libro scritto da Joseph Ratzinger-Benedetto XVI su Gesù, brano nel quale possiamo riconoscere anche l’esperienza di nostri primi Padri e di Filippo:

I modi di questa “venuta intermedia” [di Gesù] sono molteplici: il Signore viene mediante la sua parola, viene nei sacramenti, specialmente nella santissima Eucarestia; entra nella mia vita mediante parole e avvenimenti. Esistono, però, anche modi epocali di tale venuta. L’operare delle due grandi figure – Francesco e Domenico [e noi, nel nostro piccolo, possiamo aggiungere: dei Sette primi Padri e di san Filippo] – tra il XII e il XIII secolo è stato un modo in cui Cristo è entrato nuovamente nella storia, facendo valere in modo nuovo la sua parola e il suo amore; un modo in cui Egli ha rinnovato la Chiesa e mosso la storia verso di sé. […] Il suo mistero, la sua figura appare nuovamente – e soprattutto: la sua forza, che trasforma gli uomini e plasma la storia, si rende presente in modo nuovo (p. 323).

3. La Lettera spirituale di fra Angelo Maria Montorsoli

Come scrive fra Piergiorgio M. Di Domenico «la povertà è il tema specifico della sua [di fra Angelo Maria Montorsoli] Lettera universale o comune – il termine “spirituale” è dato quando la lettera sarà stampata –, uno scritto che egli indirizza a tutto l’Ordine, in obbedienza al suo maestro, il Tavanti, e nell’urgenza di una riforma che non può essere più rimandata».
Nella lettera del 28 dicembre 1596 che accompagna la spedizione della Lettera universale, il Montorsoli scriveva:

Parmi bene avertir tutti che tenghin per certo che è venuta l’hora d’haver a vivere in comune e senza proprio, o per forza o per amore, perché già per molte vie si manifesta esser tale la volontà del Signore, cui nullus resi¬stere potest

sottolineando con forza la dimensione interiore della povertà, a cui i frati sono invitati a convertirsi:

Non vi sieno di quelli che si pensi¬no haver fatto assai con rinuntiare realmente tutto quello che avevano; perché quello che vuole Iddio da noi è il cuore e non la roba; la roba più tosto in renunziarla, è com’un gettar via quello che n’impedisce all’esser seco e donarceli totalmente.

La Lettera è intesa come un contributo alla preparazione del Capitolo generale del 1597, da cui avrebbe dovuto essere eletto un Priore generale capace di far vivere tutti alla maniera religiosa, cioè di non vivere più proprietari «pur d’un quattrino». Il «tenere in proprio» è il peccato più «insostenibile e insopportabile dalla terra, perché del tutto contraddittorio e ripugnante all’essere nostro». Per il Montorsoli avere un deposito personale di danaro, da spendere liberamente, sia pure con il permesso dei superiori, è contrario alla norma fondamentale del vivere comune così come l’ha attuato la comunità apostolica di Gerusalemme. E se viene meno la radicalità di questa condivisione e comunione di beni, si smarrisce anche il senso della vita religiosa:

Il vivere in comune come facevano gli Apostoli per noi è essenziale non meno che all’uomo l’esser razionale, onde siccome tolta all’uomo la forma sua essenziale, che è l’anima ragionevole, egli non è più uomo, così tolta a noi la povertà che è vivere in comune, non siamo più noi, siamo un’altra cosa, non siamo frati, non siamo Servi di Maria, del cui ci gloriamo, né siamo di Dio, quanto alla porzione del Paradiso, finché manchiamo a lui della nostra promessa; sebben siamo di Dio, nel numero dei nemici e ribelli suoi.

Possedere in proprio è il segno di un cuore non libe¬ro; è segno di infedeltà alla perfetta sequela di Gesù povero, è disobbedienza alla volontà della Chiesa come si è espressa nei canoni di riforma del concilio di Trento; è inosservanza di quel

vivere in comune come gli apostoli del Signore, dei quali s. Agostino prese la Regola che abbiamo promesso a Dio.

4. Le nostre Costituzioni

Nella introduzione al fascicolo quinto sulla “Povertà evangelica” leggiamo:

L’argomento [della povertà evangelica] si ricollega strettamente a quello dei due fascicoli precedenti: la fraternità e la Vergine Maria. Infatti, per noi, l’idealità e la pratica della povertà si ricollegano da una parte alla fraternità originaria dei Sette santi […] e dall’altra alla pietà mariana, intesa non tanto come espressione cultuale, ma esistenziale (imitazione della vita terrena della Vergine). Risalendo alle origini cogliamo, prima di ogni età di riforma, (quella tridentina come quella attuale), una caratteristica nella vita povera dei nostri frati: la spontaneità, che si esprime senza preoccupazioni di alcuna «testimonianza», ma direttamente come risposta all’Evangelo di Cristo. Essi con questo hanno prolungato nella Chiesa del loro tempo «la presenza attiva della Madre di Gesù», prima tra i poveri del Signore ed altissimo esempio di libera disponibilità al Regno di Dio.

Piuttosto che leggere e commentare il capitolo VII sulla “Testimonianza di Povertà evangelica”, mi sono orientato alla interessante e proficua lettura dell’accurato studio di fra Faustino M. Faustini sulle nuove Costituzioni (Costituzioni dell’Ordine dei Frati Servi di Maria commentate dalle relazioni ufficiali dei Capitoli generali e del Consiglio generalizio, Roma 1989).
In relazione al capitolo sulla Testimonianza di povertà evangelica si legge nella introduzione generale:

Capitolo di Madrid (1968):
«Il titolo del capitolo VI, nell’abbozzo, era Lavoro e comunione di beni. Considerando, che il termine povertà è più vasto, includendo la nozione di lavoro, di comunione dei beni e di tenore modesto di vita, abbiamo optato per questo vocabolo povertà.
Dalla lettura dei modi sul primo abbozzo e dalle successive discussioni in commissione, apparve la necessità di precisare la nozione della povertà evangelica. Per questo la commissione ha dovuto enucleare i dati al riguardo del Nuovo Testamento e della prassi monastica, esaminando poi i risultati alla luce della problematica moderna nei confronti della testimonianza evangelica.
L’elemento fondamentale della povertà evangelica, come è proposto nel Nuovo Testamento, apparve essere la comunione.
Il testimone della povertà evangelica deve ricomporre tutta la sua umanità attorno alle parole di Cristo: Essi siano uno, come noi siamo uno (Gv 17,22).
Realtà di comunione che ritroviamo testimonianza dei nostri primi Padri, i quali, imitando Gesù Cristo, da ricchi si fecero poveri per servire; e che scopriamo, anche, dietro le asprezze del linguaggio giuridico, in quegli articoli delle Costituzioni precedenti, dove si parla della povertà. Perché, infatti, il Servo di Maria deve avere la cella dalle pareti nude (art. 86), le suppellettili povere (art. 153), non può possedere oggetti preziosi e bisogna che sia contento del necessario (art. 157), se non perché non deve sentirsi se-parato per una maggiore ricchezza dai poveri?
Quindi in comunione con loro.
Il nostro tempo, nel processo di una sempre maggior produzione di beni, viene a porre l’umanità nel rischio di subordinare l’essere all’avere, la vita alla proprietà; domanda a chi professa la povertà del Vangelo un’aggiunta di apertura cristiana: la comunione.
Tale aggiunta di apertura è chiaramente indicata dalla Lumen Gentium, 36: I beni creati siano fatti progredire dal lavoro umano… per l’utilità di tutti assolutamente gli uomini.
La testimonianza della povertà è, quindi, l’accettazione di un’aggiunta di apertura ai beni posseduti, perché siano trasformati da oggetto di attività in mezzo di comunicazione e di scambio di vita.
La testimonianza della povertà domanda così: l’abolizione di ogni separazione dagli altri. Il lavoro è assunto per condividere la sorte di tutti gli uomini; la comunione di beni toglie ogni forma di possesso e quindi di separazione; la rinuncia ad ogni lusso, seguendo il tenore modesto di vita, mette in comunione con chi ne è privo.
La presentazione del capitolo VII fu seguita da una lunga discussione sul termine povertà e sul suo contenuto.
Fu contestato l’uso della parola, almeno in inglese, perché nel linguaggio corrente significava una condizione di vita molto indigente e non un tenore medio, quale abitualmente era il nostro. La non corrispondenza con il significato corrente, generava confusione e disagio.
Ne fu invece difeso l’uso nell’accezione intesa dalla Chiesa (specialmente nel Concilio Vaticano II) e dalla tradizione della vita religiosa. In questa specifica accezione, la parola povertà era accettabile anche in inglese. Per maggiore chiarezza, venne aggiunto l’aggettivo evangelica al termine povertà.
Rispetto al contenuto della parola, vi fu chi sostenne un genere di vita corrispondente a quello della maggior parte delle persone fra cui si vive. Non alieno dalle normali comodità e dagli strumenti utili di lavoro. La povertà si qualificava particolarmente per il distacco interiore.
Vi era chi suggeriva l’abolizione di possessi superflui, immobiliari o bancari.

Capitolo di Barcellona (1977)
[…] Il concetto base di povertà nelle nostre Costituzioni è la comunione dei beni: il condividere tutto con tutti. Da questo concetto consegue il dovere del lavoro e del modesto tenore di vita per la comunità e i singoli. Anche il Capitolo generale di Roma si è espresso quasi con le stesse parole dell’articolo 56.

5. Le linee ispirazionali del Capitolo generale 2007

Il fiore più recente del grande albero della nostra plurisecolare tradizione in relazione alla povertà evangelica è il documento posto all’inizio dei Testi del Capitolo generale 2007, La povertà evangelica, un ritorno all’essenziale: linee ispiratrici.
Richiamo solamente un punto di invito alla riflessione del testo:

La povertà del Servo di Maria non è la scelta di una perfezione individuale. Eppure concerne me personalmente, che sento di non vivere secondo povertà, che non sono libero nel cuore dal desiderio di cose, che non manco di nulla e tuttavia mi sono creato molte inutili esigenze, che ho capovolto la parola della Regola di sant’Agostino: è meglio aver meno bisogni che possedere più cose (Regola 18). Quali cose io devo lasciare? Io, che sperimento la tensione e la distanza tra la proposta radicale del Vangelo e i poveri passi che con fatica riesco a fare, che mentre continuo a cercare accorgimenti per giustificarmi accantono l’urgenza di decidere …
Il Vangelo ci chiede ben di più, esige un cambiamento della nostra vita. Se l’ideale è solo proclamato, è dannoso; se la Parola non si incarna in scelte concrete, è non solo svuotata ma pericolosa: la mia e nostra incoerenza ne escono rafforzate. (n. 1

1Significativo punto di riferimento sono due pubblicazioni: il quinto fascicolo della Commissione per lo studio delle Costituzioni dal titolo Povertà evangelica, che vide i contributi di Franco Andrea Dal Pino, Giovanni Maria Vannucci, Luigi Maria De Candido e Peregrine Maria Graffius; ed il volume dei Quaderni di Monte Senario n. 13, dal titolo: La povertà dai movimenti laici medioevali alle istanze evangeliche. Pensieri ed esperienze nella Famiglia dei Servi ieri e oggi, edito dalla comunità di Monte Senario nel 2003.

2Le domande che il Papa ha fatto a tutti i fedeli nell’omelia della Messa in Coena Domini di quest’anno 2011 sono un aiuto a noi. In quell’occasione Benedetto XVI diceva: «Gesù ha desiderio di noi, ci attende. E noi, abbiamo veramente desiderio di Lui? C’è dentro di noi la spinta ad incontrarLo? Bramiamo la sua vicinanza, il diventare una cosa sola con Lui, di cui Egli ci fa dono nella santa Eucaristia? Oppure siamo indifferenti, distratti, pieni di altro? Dalle parabole di Gesù sui banchetti sappiamo che Egli conosce la realtà dei posti rimasti vuoti, la risposta negativa, il disinteresse per Lui e per la sua vicinanza. I posti vuoti al banchetto nuziale del Signore, con o senza scuse, sono per noi, ormai da tempo, non una parabola, bensì una realtà presente, proprio in quei Paesi ai quali Egli aveva manifestato la sua vicinanza particolare. Gesù sapeva anche di ospiti che sarebbero sì venuti, ma senza essere vestiti in modo nuziale – senza gioia per la sua vicinanza, seguendo solo un’abitudine, e con tutt’altro orientamento della loro vita. San Gregorio Magno, in una delle sue omelie, si domandava: Che genere di persone sono quelle che vengono senza abito nuziale? In che cosa consiste questo abito e come lo si acquista? La sua risposta è: Quelli che sono stati chiamati e vengono hanno in qualche modo fede. È la fede che apre loro la porta. Ma manca loro l’abito nuziale dell’amore. Chi vive la fede non come amore non è preparato per le nozze e viene mandato fuori. La comunione eucaristica richiede la fede, ma la fede richiede l’amore, altrimenti è morta anche come fede».una decisione non presa alla leggera e come per caso, ma con matura e salda deliberazione, sotto l’impulso speciale della Nostra Signora
3P.G.M. DI DOMENICO, Capitoli di storia della povertà tra i Servi, in QMS13, pp. 77-94.

This a powerpoint presentation (italian) of the recent Servite International Meeting of Secretariats and Officials. The meeting centered on the theme of the General chapter 2007, on Evangelical Poverty. There were 38 participants (including 2 translators) from Europe, America, Asia and Africa. The main objective of the said meeting was to promote spiritual progress among friars of all ages, and a clear understanding of the world (through country report) we live in. It was organized as an on-going formation  for groups of friars in various areas of pastoral concern (formation,parish, shrine, education, compassion, justice and peace, chaplaincies,  and other ministrie), with special emphasis on friars who have been solemnly professed for five years.

Earth, Our Home

Humanity is part of a vast evolving universe. Earth, our home, is alive with a unique community of life. The forces of nature make existence a demanding and uncertain adventure, but Earth has provided the conditions essential to life’s evolution. The resilience of the community of life and the well-being of humanity depend upon preserving a healthy biosphere with all its ecological systems, a rich variety of plants and animals, fertile soils, pure waters, and clean air. The global environment with its finite resources is a common concern of all peoples. The protection of Earth’s vitality, diversity, and beauty is a sacred trust.

The Global Situation

The dominant patterns of production and consumption are causing environmental devastation, the depletion of resources, and a massive extinction of species. Communities are being undermined. The benefits of development are not shared equitably and the gap between rich and poor is widening. Injustice, poverty, ignorance, and violent conflict are widespread and the cause of great suffering. An unprecedented rise in human population has overburdened ecological and social systems. The foundations of global security are threatened. These trends are perilous—but not inevitable.

The Challenges Ahead

The choice is ours: form a global partnership to care for Earth and one another or risk the destruction of ourselves and the diversity of life. Fundamental changes are needed in our values, institutions, and ways of living. We must realize that when basic needs have been met, human development is primarily about being more, not having more. We have the knowledge and technology to provide for all and to reduce our impacts on the environment. The emergence of a global civil society is creating new opportunities to build a democratic and humane world. Our environmental, economic, political, social, and spiritual challenges are interconnected, and together we can forge inclusive solutions.

Universal Responsibility

To realize these aspirations, we must decide to live with a sense of universal responsibility, identifying ourselves with the whole Earth community as well as our local communities. We are at once citizens of different nations and of one world in which the local and global are linked. Everyone shares responsibility for the present and future well-being of the human family and the larger living world. The spirit of human solidarity and kinship with all life is strengthened when we live with reverence for the mystery of being, gratitude for the gift of life, and humility regarding the human place in nature.

We urgently need a shared vision of basic values to provide an ethical foundation for the emerging world community. Therefore, together in hope we affirm the following interdependent principles for a sustainable way of life as a common standard by which the conduct of all individuals, organizations, businesses, governments, and transnational institutions is to be guided and assessed.

Principles

I. RESPECT AND CARE FOR THE COMMUNITY OF LIFE
1. Respect Earth and life in all its diversity.
a. Recognize that all beings are interdependent and every form of life has value regardless of its worth to human beings.
b. Affirm faith in the inherent dignity of all human beings and in the intellectual, artistic, ethical, and spiritual potential of humanity.

2. Care for the community of life with understanding, compassion, and love.
a. Accept that with the right to own, manage, and use natural resources comes the duty to prevent environmental harm and to protect the rights of people.
b. Affirm that with increased freedom, knowledge, and power comes increased responsibility to promote the common good.

3. Build democratic societies that are just, participatory, sustainable, and peaceful.
a. Ensure that communities at all levels guarantee human rights and fundamental freedoms and provide everyone an opportunity to realize his or her full potential.
b. Promote social and economic justice, enabling all to achieve a secure and meaningful livelihood that is ecologically responsible.

4. Secure Earth’s bounty and beauty for present and future generations.
a. Recognize that the freedom of action of each generation is qualified by the needs of future generations.
b. Transmit to future generations values, traditions, and institutions that support the long-term flourishing of Earth’s human and ecological communities.

In order to fulfill these four broad commitments, it is necessary to:

II. ECOLOGICAL INTEGRITY
5. Protect and restore the integrity of Earth’s ecological systems, with special concern for biological diversity and the natural processes that sustain life.

a. Adopt at all levels sustainable development plans and regulations that make environmental conservation and rehabilitation integral to all development initiatives.
b. Establish and safeguard viable nature and biosphere reserves, including wild lands and marine areas, to protect Earth’s life support systems, maintain biodiversity, and preserve our natural heritage.
c. Promote the recovery of endangered species and ecosystems.
d. Control and eradicate non-native or genetically modified organisms harmful to native species and the environment, and prevent introduction of such harmful organisms.
e. Manage the use of renewable resources such as water, soil, forest products, and marine life in ways that do not exceed rates of regeneration and that protect the health of ecosystems.
f. Manage the extraction and use of non-renewable resources such as minerals and fossil fuels in ways that minimize depletion and cause no serious environmental damage.

6. Prevent harm as the best method of environmental protection and, when knowledge is limited, apply a precautionary approach.
a. Take action to avoid the possibility of serious or irreversible environmental harm even when scientific knowledge is incomplete or inconclusive.
b. Place the burden of proof on those who argue that a proposed activity will not cause significant harm, and make the responsible parties liable for environmental harm.
c. Ensure that decision making addresses the cumulative, long-term, indirect, long distance, and global consequences of human activities.
d. Prevent pollution of any part of the environment and allow no build-up of radioactive, toxic, or other hazardous substances.
e. Avoid military activities damaging to the environment.

7. Adopt patterns of production, consumption, and reproduction that safeguard Earth’s regenerative capacities, human rights, and community well-being.
a. Reduce, reuse, and recycle the materials used in production and consumption systems, and ensure that residual waste can be assimilated by ecological systems.
b. Act with restraint and efficiency when using energy, and rely increasingly on renewable energy sources such as solar and wind.
c. Promote the development, adoption, and equitable transfer of environmentally sound technologies.
d. Internalize the full environmental and social costs of goods and services in the selling price, and enable consumers to identify products that meet the highest social and environmental standards.
e. Ensure universal access to health care that fosters reproductive health and responsible reproduction.
f. Adopt lifestyles that emphasize the quality of life and material sufficiency in a finite world.

8. Advance the study of ecological sustainability and promote the open exchange and wide application of the knowledge acquired.
a. Support international scientific and technical cooperation on sustainability, with special attention to the needs of developing nations.
b. Recognize and preserve the traditional knowledge and spiritual wisdom in all cultures that contribute to environmental protection and human well-being.
c. Ensure that information of vital importance to human health and environmental protection, including genetic information, remains available in the public domain.

III. SOCIAL AND ECONOMIC JUSTICE
9. Eradicate poverty as an ethical, social, and environmental imperative.
a. Guarantee the right to potable water, clean air, food security, uncontaminated soil, shelter, and safe sanitation, allocating the national and international resources required.
b. Empower every human being with the education and resources to secure a sustainable livelihood, and provide social security and safety nets for those who are unable to support themselves.
c. Recognize the ignored, protect the vulnerable, serve those who suffer, and enable them to develop their capacities and to pursue their aspirations.

10. Ensure that economic activities and institutions at all levels promote human development in an equitable and sustainable manner.
a. Promote the equitable distribution of wealth within nations and among nations.
b. Enhance the intellectual, financial, technical, and social resources of developing nations, and relieve them of onerous international debt.
c. Ensure that all trade supports sustainable resource use, environmental protection, and progressive labor standards.
d. Require multinational corporations and international financial organizations to act transparently in the public good, and hold them accountable for the consequences of their activities.

11. Affirm gender equality and equity as prerequisites to sustainable development and ensure universal access to education, health care, and economic opportunity.
a. Secure the human rights of women and girls and end all violence against them.
b. Promote the active participation of women in all aspects of economic, political, civil, social, and cultural life as full and equal partners, decision makers, leaders, and beneficiaries.
c. Strengthen families and ensure the safety and loving nurture of all family members.

12. Uphold the right of all, without discrimination, to a natural and social environment supportive of human dignity, bodily health, and spiritual well-being, with special attention to the rights of indigenous peoples and minorities.
a. Eliminate discrimination in all its forms, such as that based on race, color, sex, sexual orientation, religion, language, and national, ethnic or social origin.
b. Affirm the right of indigenous peoples to their spirituality, knowledge, lands and resources and to their related practice of sustainable livelihoods.
c. Honor and support the young people of our communities, enabling them to fulfill their essential role in creating sustainable societies.
d. Protect and restore outstanding places of cultural and spiritual significance.

IV. DEMOCRACY, NONVIOLENCE, AND PEACE
13. Strengthen democratic institutions at all levels, and provide transparency and accountability in governance, inclusive participation in decision making, and access to justice.
a. Uphold the right of everyone to receive clear and timely information on environmental matters and all development plans and activities which are likely to affect them or in which they have an interest.
b. Support local, regional and global civil society, and promote the meaningful participation of all interested individuals and organizations in decision making.
c. Protect the rights to freedom of opinion, expression, peaceful assembly, association, and dissent.
d. Institute effective and efficient access to administrative and independent judicial procedures, including remedies and redress for environmental harm and the threat of such harm.
e. Eliminate corruption in all public and private institutions.
f. Strengthen local communities, enabling them to care for their environments, and assign environmental responsibilities to the levels of government where they can be carried out most effectively.

14. Integrate into formal education and life-long learning the knowledge, values, and skills needed for a sustainable way of life.
a. Provide all, especially children and youth, with educational opportunities that empower them to contribute actively to sustainable development.
b. Promote the contribution of the arts and humanities as well as the sciences in sustainability education.
c. Enhance the role of the mass media in raising awareness of ecological and social challenges.
d. Recognize the importance of moral and spiritual education for sustainable living.

15. Treat all living beings with respect and consideration.
a. Prevent cruelty to animals kept in human societies and protect them from suffering.
b. Protect wild animals from methods of hunting, trapping, and fishing that cause extreme, prolonged, or avoidable suffering.
c. Avoid or eliminate to the full extent possible the taking or destruction of non-targeted species.

16. Promote a culture of tolerance, nonviolence, and peace.
a. Encourage and support mutual understanding, solidarity, and cooperation among all peoples and within and among nations.
b. Implement comprehensive strategies to prevent violent conflict and use collaborative problem solving to manage and resolve environmental conflicts and other disputes.
c. Demilitarize national security systems to the level of a non-provocative defense posture, and convert military resources to peaceful purposes, including ecological restoration.
d. Eliminate nuclear, biological, and toxic weapons and other weapons of mass destruction.
e. Ensure that the use of orbital and outer space supports environmental protection and peace.
f. Recognize that peace is the wholeness created by right relationships with oneself, other persons, other cultures, other life, Earth, and the larger whole of which all are a part.

The Way Forward

As never before in history, common destiny beckons us to seek a new beginning. Such renewal is the promise of these Earth Charter principles. To fulfill this promise, we must commit ourselves to adopt and promote the values and objectives of the Charter.

This requires a change of mind and heart. It requires a new sense of global interdependence and universal responsibility. We must imaginatively develop and apply the vision of a sustainable way of life locally, nationally, regionally, and globally. Our cultural diversity is a precious heritage and different cultures will find their own distinctive ways to realize the vision. We must deepen and expand the global dialogue that generated the Earth Charter, for we have much to learn from the ongoing collaborative search for truth and wisdom.
Life often involves tensions between important values. This can mean difficult choices. However, we must find ways to harmonize diversity with unity, the exercise of freedom with the common good, short-term objectives with long-term goals. Every individual, family, organization, and community has a vital role to play. The arts, sciences, religions, educational institutions, media, businesses, nongovernmental organizations, and governments are all called to offer creative leadership. The partnership of government, civil society, and business is essential for effective governance.

In order to build a sustainable global community, the nations of the world must renew their commitment to the United Nations, fulfill their obligations under existing international agreements, and support the implementation of Earth Charter principles with an international legally binding instrument on environment and development.

Let ours be a time remembered for the awakening of a new reverence for life, the firm resolve to achieve sustainability, the quickening of the struggle for justice and peace, and the joyful celebration of life.

About 80 percent of the American public believes it is more dangerous to generate electricity from nuclear power than from coal. Scientific studies show, however, than coal is many times more dangerous. Even Henry Kendall, director of the anti-nuclear lobbying group Union of Concerned Scientists, and anti-nuclear activist Ralph Nader, in private, concede this.

The enormous public misunderstanding about nuclear power may be largely attributed to (1) a widespread and exaggerated fear of radiation, (2) a highly distorted picture of reactor accidents (3) grossly unjustified fears about disposal of radioactive waste, and (4) failure to understand and quantify risk.

RADIATION
How Dangerous Is Radiation?
Is being struck by a particle of radiation a terrible tragedy? No. Every person is struck by about a million particles of radiation every minute from natural sources. (The rate varies with geography and other factors.) This rate is hundreds of times greater than our exposure to radiation from the nuclear power industry. So is our average exposure to radiation from medical X-rays.

Although a single particle of radiation can cause cancer, the chance it will do so is only about one in 30 quadrillion. Hence, the million particles that strike us each minute have only one chance in 30 billion of causing a cancer. A human lifespan is about 40 million minutes; thus, all of the natural radiation to which we are exposed has about one chance in 700 of causing a cancer. Since our overall chance of dying from cancer is one in five, only one in 140 of all cancers may be due to natural radiation. The average exposure from a nuclear power plan to those who live closest to it is about 1 percent of the exposure to natural radiation; hence, if they live there for a lifetime, there is perhaps once chance in 70,000 (1/100th the chance from natural radiation and 1/14,000 the chance from all causes) that they will die of cancer as a result of exposure to its radiation.

Scientific Basis for Risk Estimates
How do we know these risks so quantitatively? Several prestigious scientific groups provide frequent summaries and evaluations of available data. In the past few years, the US National Academy of Sciences Committee on Biological Effects of Ionizing Radiation (BEIR) and the United National Scientific Committee on Effects of Atomic Radiation (UNSCEAR) have issued reports assessing the cancer risk from low-level radiation. There should be one extra cancer for every 2.6 million mrem (1 millirem = approximately 5 billion particles of radiation) of exposure to humans, i.e., every mrem of exposure produces a 1-in-2.6-million risk of fatal cancer.

The health effects of high-level radiation are well known and serious. But there is little direct evidence on effects of low-level radiation. The simplest way to make estimates is to derive them from data on high-level radiation by assuming a linear dose-effect relationship. For example, if high-level dose D causes a cancer risk R, we assume that a dose 0.01 D will cause a risk 0.01 R. This assumption is nearly always used, with relatively minor variations. It was used to drive the estimate of one cancer death per 2.6 million mrem given above. However, this is more likely to overestimate than to underestimate the effects of low-level radiation, and the minor variations from linear behavior often used are such as to reduce, moderately, the estimated effects at low levels. This may be described graphically by stating that the curve of cancer risk vs. radiation does is concave upward, i.e., it curves upward at high dose from a simple straight line. There is abundant evidence supporting this viewpoint.

Routine Emissions from the Nuclear Industry
In operation, nuclear power plants routinely release small quantities of radioactive gases and contaminants in water into the environment. More importantly, when reactor fuel is chemically reprocessed, more radioactive gases are released at the reprocessing plant. Extensive studies predict that, with current technology, routine releases of radiation due to operation of one large power plant for one year, including reprocessing, will cause 0.25 cancer deaths over the next 500 years. Since we are not reprocessing fuel now, effects of current operations are only about 20 percent of this. Available technologies can drastically reduce releases from reprocessing plants.

REACTOR ACCIDENTS
Power plants include many levels of protection against radioactivity releases, based on a defense in depth design philosophy. For example, an accident could be initiated by a sudden rupture in the system, allowing the cooling water to escape. Levels of protection against this are:

1.the highest quality standards on materials and equipment in which such a rupture might occur;
2.elaborate inspection programs to detect flaws in the system using X-ray, ultrasonic, and visual techniques;
3.leak-detection systems (Normally a rupture starts out as a small crack, allowing water to leak out slowly. Such leaks would be detected by these systems and repaired before a rupture could occur.);
4.an emergency cooling system, which would rapidly replace the water lost in such a rupture accident, restoring cooling to the reactor fuel. (In this type of accident there are several different pumping systems, any one of which would provide sufficient water to avert a meltdown if all the other somehow failed.);
5.the containment, a strong building in which the reactor is housed, which would normally hold the released radioactivity inside even if there were a meltdown.
Occasionally there is a failure at some power plant in one of these lines of defense, e.g., a valve that should be open is found closed. The media report this as a near miss or a disaster, apparently not understanding defense in depth. While it is possible for each line of defense to fail, one after another, the probability of such a sequence is extremely low. Moreover, the same reasoning applies to almost any other technology. In pumping gasoline, for example, a highly improbable sequence of highly improbably events could burn down a city, killing most of its inhabitants, yet the media do not trumpet warning of these impending catastrophes.

How large is the risk to the public from a reactor accident? The scientific approach to this problem is through Probabilistic Risk Analysis (PRA), which, in principle, considers every combination of events that can lead to health impacts, along with their probability of occurrence. The individual events are failures of valves, pumps, welds, and such, for which there are abundant data on frequency. It is therefore not difficult to determine the probability for any given sequence of events. PRA have completed on about 30 plants and will soon be available for all US plants. We give typical results here. We also give results from a study by the anti-nuclear activist organization, Union of Concerned Scientists.11

For the frequency, the PRA give one meltdown per 10,000 plant-years, whereas the UCS estimate is one per 2,000 plant-years. After about 4,000 plant-years of commercial operation of this type reactor around the world and about 3,000 equivalent plant-years of naval reactor operation, there has been only one fuel damage accident, Three Mile Island.* Thus, the UCS estimate implies that we have been extremely lucky, although these results are not surprising based on PRA.

There is widespread misunderstanding of the consequences of a fuel meltdown. We often hear that it would kill tens of thousands of people and contaminate a whole state, but such statements are grossly misleading. The containment building would ordinarily contain the radioactive dust inside long enough (about a day) to clean it out of the air. For example, investigators of the Three Mile Island accident12 all agree that even if there had been a complete meltdown, there would have been little harm to the public, because there is not reason to believe that the integrity of the containment would have been compromised. In most meltdown, no fatalities are to be expected.

Some events could break open the containment building, releasing radioactive dust into the environment. If this happens, the consequences depend on timing and weather. In the most unfavorable condition, with a large containment break early in the accident, PRA estimates 50,000 fatalities in some cases, but this unusual combination is expected only once in 100,000 meltdowns, i.e., about once in a billion plant years.

According to PRA, the average number of fatalities to be expected in a reactor meltdown is 400; according to UCS, it is 5,000. Estimates of the fatality rate due to air pollution from coal burning are at least 10,000 each year.13 For reactor meltdown to be as harmful as coal-burning, we would therefore need a meltdown every two weeks according to the PRA, or every six months according to UCS. No one has suggested that meltdowns will occur anywhere near that frequently.

When the frequency and consequence estimates are combined, the Nuclear Regulatory Commission concludes that we may expect an average of 0.02 fatalities per plant-year; UCS predicts 2.4. Even the latter figure is less than one-tenth the 25 fatalities per plant-year due to air pollution from coal-burning electricity generation.13 Of course these fatalities from air pollution are not detectable in the US population, in which two million people die every year. But the same would be true of 98 percent of the predicted fatalities from reactor meltdown accidents. For example, the worst such accident normally considered would cause 45,000 extra cancer deaths in a population of ten million over 50 years. For each of these ten million, the risk of dying from cancer would rise by only 2.5 percent, which would hardly be detectable. The present risk in different states varies between 16 percent and 24 percent, so the added cancer risk in moving from one state to another is often many times larger than the added risk from such a nuclear accident.

Detectable fatalities — occurring shortly after the hypothetical accident and clearly attributable to it – would be rather rare. According to PRA, 98 percent of all meltdowns would cause no detectable fatalities, the average number for all meltdowns is ten, and the worst meltdown in the analyses (1 1-in-100,000 occurrence) would cause 3,500. The largest coal-related incident to date was an air pollution episode in London in 1952 that cased 3,500 fatalities within a few days.13 Thus, as far as detectable fatalities are concerned, the worst nuclear accident in 100,000 meltdowns has already been equaled by coal burning.

The extent of land contamination in a reactor meltdown accident depends on one’s definition of contamination. The whole earth can be said to be contaminated because there is natural radioactivity everywhere. But if we use the internationally accepted definition of the level that calls for remedial action, the worst meltdown normally considered (one in 10,000) would contaminate an area equal to a circle 60 miles in diameter. About 90 percent of this could be easily decontaminated by use of fire hoses and plowing open fields, so the area where relation of people is necessary would be equal to that of a circle 20 miles across. Forced relocation of people is not catastrophic. It occurs when new dams permanently flood large areas, in highway construction, in urban redevelopment, etc. In such situations the major consideration is the cost of relocating people. Therefore, it seems reasonable to consider land contamination by a nuclear accident on the basis of its monetary cost.

In the worst 0.01 percent of accidents, the cost could exceed $30 billion, but the average cost for all meltdowns would be $200 million. Air pollution from coal burning also does property damage, estimated in the range of $1 billion per year.14 At an average of $200 million per meltdown, it would take a reactor meltdown every two months to be as costly as the property damage from coal burning.

RADIOACTIVE WASTE
There are several types of radioactive waste generated by the nuclear industry, but we will concentrate largely on the two most important and potentially dangerous, high-level waste and radon.

High-Level Waste 15
In a rationally planned and developed nuclear power program, spent reactor fuel would be shipped to a reprocessing plant to remove valuable components. The residue, containing nearly all of the radioactivity produced in the reactor, is called high-level waste. (In the US program, where spent fuel is simply potted and encased, reprocessing is not currently done or even planned, but it is done in other countries.) Following reprocessing, the waste can be converted into a rock-like form and buried deep underground in a carefully selected geological formation.

One important aspect of high-level waste disposal is the small quantities involved. The waste generated by one large nuclear power plant in one year and prepared for burial is about six cubic yards, roughly one truckload. This is two million times smaller by weight, and billion of times smaller by volume, than wastes from a coal plant. The electricity generated in a year sells for more than $400 million, so if only 1 percent of the sales price were diverted to waste disposal, $4 million might be spent to bury this one truckload of waste, enough to pay for very elaborate protective measures.

To understand the very long-term (millions of years) hazard, natural radioactivity in the ground is a good comparison. The ground is full of naturally radioactive materials. By adding nuclear waste to it, the totally radioactivity in the top 2,000 feet of US soil would increase by one part in ten million per plant-year. Moreover, the radioactivity in the ground (except perhaps very near the surface) does virtually no harm.

The principal concern about buried waste is that it might dissolve in groundwater and contaminate food and drinking water supplies. How dangerous is this material to eat or drink? When first buried, it is highly toxic, and a fatal dose (yielding a 50 percent chance of death) is only 0.01 ounce. However, after 100 years the fatal dose is 0.1 ounce, and after 600 years it is one ounce, making it no more toxic than many common household chemicals and medicines. After 10,000 years a lethal dose is ten ounces.

Some people are frightened on hearing that nuclear waste must be isolated for a few hundred years. But 2,000 feet below earth’s surface, things remain essentially unchanged for millions of years. Waste burial plans include measures to delay the release of the waste to the environment for a very long time, yielding near-perfect protection from the short-term (several hundred or thousand years) problem. First, wastes will be buried in rock formations isolated from groundwater and expected to remain so for at least 1,000 years. Second, if water did enter, it would be no more likely to dissolve the waste than the surrounding rock; for the latter the time required is ordinarily millions of years. Third, clay backfill materials surrounding the waste package swell up to seal very tightly when wet, keeping out any appreciable amount of water. Fourth, if groundwater did reach and dissolve some of the waste, these clays would effectively filter radioactive material out of solution before it could escape with the water. Also, waste will be sealed in corrosion-resistant casings that would not dissolve even if soaked in groundwater for many thousands of years. Finally, if radioactivity did reach surface waters, it would be detected easily — a millionth of the amounts that can be very harmful are readily detected — and measure could be taken to prevent it from getting into drinking water or food.

With all these safeguards it seems almost impossible for much harm to result during the first few hundred years, while the waste is highly toxic and there is substantial protection over the long term.

It can be helpful to compare radioactive waste with ordinary rock. An average atom of rock has about one chance in a billion per year of escaping into surface waters and one in a thousand of getting into a human body afterward. If these probabilities are combined and applied to buried radioactive waste, the result indicates that the waste would eventually cause 0.02 fatalities per plant-year — a thousand times less than the health effects of air pollution from coal burning.

Rational risk assessment considers alternatives. Nuclear wastes remain radioactive for thousands or even millions of years, but some cancer-causing solid wastes released in coal-burning — like arsenic, beryllium, cadmium, chromium, and nickel — last forever. They can be expected to cause about 70 eventual fatalities per plant-year, thousands of times more than nuclear waste. Also, solar electricity technologies require vast amounts of materials, and deriving these requires burning large quantities of coal. The waste from solar technologies are many times more harmful than nuclear wastes. In addition, some solar technologies use large quantities of cadmium, which increases the health consequences considerably.15

Radon Problems 16
Another aspect of nuclear waste may involve important health impacts: the release of radon, a radioactive gas that naturally evolves from uranium. There has been some concern over increased releases of radon due to uranium mining and milling operations. These problems have now been substantially reduced by cleaning up those operations and covering the residues with several feet of soil. The health effects of this radon are several times larger than those from other nuclear wastes, such as the high-level waste discussed above, but they are still much smaller than the effects of coal-burning.

However, a far more important impact of the nuclear industry on radon is that by mining uranium out of the ground, we avert future radon emissions and thus avoid future health impacts. Most of the uranium is mined from deep underground, so one might think the radon could not escape. However, the ground surface is constantly eroding away, so eventually the uranium mined would have been near the surface, where it radon emissions could cause lung cancers. When these effects are calculated, the result is an eventual saving of 450 lives per plant-year operation. This saving is thousands of times larger than the lives calculated to be lost from radioactive waste. Also, coal burning releases small amounts of uranium into the environment, eventually causing 30 fatalities per plant-year through radon released.

Summary on Waste
The number of deaths per plant-year estimated in the preceding discussion (plus a few others) is summarized in Table 1. Since many people (including myself) feel that it is meaningless to consider effects over many millions of years, a column has also been included summarizing effects realized over the next 500 years. It should be understood that the minus signs on the numbers for radon from nuclear power indicate lives saved rather than lost. Note that there are three types of waste from coal burning, each of which is thousands of times more harmful than the nuclear waste.

Table 1: Deaths per 1,000 MW plant per year of operation due to wastes Source Next 500 years Millions of years
Nuclear:
– high-level waste 0.0001 0.02
– radon emissions -0.0650 -450
– low-level waste 0.0001 0.0004
– total -0.0648 -450
Coal:
– air pollution 25 25
– radon emissions 0.11 30
– cancer-causing chemicals 0.5 70
– total 25.61 125
Solar photovoltaics:
– coal for materials 0.8 3.7
– cadmium sulfide (if used) 0.8 80
– total 1.6 83.7

RISKS IN PERSPECTIVE 17
Risks are commonly stated in terms of probabilities of death at various ages, but to make them more understandable we express them as loss of life expectancy (LLE) (see Figure 1 below). (An LLE of one day does not mean that each person will die one day sooner but that the average shortening of each life is one day — true if one person in a thousand dies 1,000 days earlier while 999 are unaffected.) The LLE for nuclear power is about one hour (0.04 day) according to most scientific estimates, or 1.5 days according to the Union of Concerned Scientists. The LLE for coal-burning pollution is about 13 days, from oil burning about 4.5 days, and from natural gas about 2.5 days. This makes the LLE from nuclear generation from 8 to 300 times less than from coal, 3 to 100 times less than from oil, and 1.7 to 60 times less than from natural gas. To put these numbers in perspective, we show in Figure 1 the LLE from some other common risks we face.17 Notice that even energy conservation bears risks: radon trapped by tighter housing construction; smaller, riskier cars; more crimes and accidents in reduced lighting; etc. Any one of these items makes energy conservation much more risky than nuclear power.

——————————————————————————–
Figure 1: Comparison of risks. Length of bar is LLE. Asterisk denotes average risk over the total US population; others refer to risks of those exposed or participating. The ordinate scale is shown at top. The length of the bars are multiplied by 20 in the center scetion and by 1,000 in the bottom section. The first bar in each section reproduces the last bar in the previous section, showing the effect of the scale change.
Far more important is the danger that over-zealous conservation may reduce our wealth. In the United States, well-to-do people live ten years longer than poor people. Producing wealth requires a lot of energy. Therefore, it conserving energy reduces wealth, the ultimate health risks from conservation would dwarf the few hours LLE from nuclear power.

Another way to put the risks of nuclear energy into perspective is to show what other risks they are equivalent to. To make this non-controversial, we use both the PRA and UCS estimates for risks of nuclear power, the latter in parentheses. The risks from having all electricity in the United States generated by nuclear power are equivalent to the following risks:

1.a regular smoker smoking one extra cigarette every 15 years (3 months);
2.an overweight person increasing his weight by 0.012 ounce (0.8 ounce);
3.raising the highway speed limit from 55 to 55.006 (55.6) miles per hour.
WHY THE PUBLIC MISUNDERSTANDING?
Why are the risks of nuclear power so grossly exaggerated in the public mind? The public gets most of its information from the news media, so the media are responsible. Stories about dangers of radiation are exciting and therefore get wide coverage. Yet there has not been a single fatal accident in the United States involving radiation for 25 years, during which there have been three million fatalities from other accidents. Members of the media generally do not read the scientific literature. The contact with science if often through a few publicity-seeking scientists who tell them what they want to hear. Any scientist who reports the slightest evidence that makes radiation seem dangerous gets tremendous coverage, while contrary evidence is generally ignored.

As a consequence, all new power plants ordered for the past several years been coal burners. Yet every time a coal-burning plant is built instead of a nuclear plant, many hundreds of people are condemned to premature death.

NOTES
1.This chapter is based on B.L. Cohen, The Nuclear Energy Option. New York: Plenum, 1990.
2.Opinion Research Corp. “Public Attitudes Towards Nuclear Power vs. Other Energy Sources,” ORC Public Opinion Index, 38, 17 (September 1980).
3.National Academy of Sciences Committee on Nuclear and Alternative Energy Systems, Energy in Transition, 1985-2010. San Francisco: W.H. Freeman, 1980; American Medical Association Council on Scientific Affairs, “Health evaluation of energy generating sources.” Journal of the American Medical Association, 240 (1978), 2193; Nuclear Energy Policy Study Group, Nuclear Power — Issues and Choices. Cambridge, MA: Ballinger, 1977; Union of Concerned Scientists, The Risks of Nuclear Power Reactors; United Kingdom Health and Safety Executive, Comparative Risks of Electricity Production Systems (1980). Norwegian Ministry of Oil and Energy, Nuclear Power and Safety (1978); Science Advisory Office, State of Maryland, Coal and Nuclear Power (1980); Legislative Office of Science Advisor, State of Michigan, Coal and Nuclear Power (1980); H. Fisher, et al., “Comparative Effects of Different Energy Technologies,” Brookhaven National Laboratory Report BNL 51491 (1981); American Medical Association Council on Scientific Affairs, “Medical Perspective on Nuclear Power” (1989).
4.H. Kendall, Physics Colloquium, at Carnegie-Mellon University (1980).
5.In answer to my question, Nader replied, “Maybe we can clean up coal, or maybe we shouldn’t burn coal either.”
6.National Academy of Sciences Committee on Biological Effects of Ionizing Radiation (BEIR-V), Health Effects of Exposure to Low Levels of Ionizing Radiation. Washington: 1990. A large number of references if given.
7.United Nations Scientific Committee on Effects of Atomic Radiation (UN-SCEAR), Sources, Effects and Risks of Ionizing Radiation. New York: United Nationals, 1988. A large number of references is given.
8.B.L. Cohen. “The Cancer Risk from Low Level Radiation.” Health Physics, 39 (1980), 659. Many references are given. (A few papers have purported to give evidence that the cancer risk vs. dose curve is concave downward, which would indicate that the linear assumption underestimates the risk of low-level radiation. Each of these, however, has been severely criticized in the scientific literature and has been rejected by all groups charged with responsibilities in radiation protection.)
9.Many people think that a nuclear reactor can explode like an atomic bomb, but technical arguments easily prove that his is absolutely impossible.
10.Reactor Safety Study, Nuclear Regulatory Commission Document WASH-1400, NUREG 75/014 (1975); “Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants,” Nuclear Regulatory Commission Document RUEG-1150 (1989).
11.Union of Concerned Scientists. The Risks of Nuclear Power Reactors (Cambridge, MA: 1977). They give 2.4 deaths/GWe-year, which, multiplied by 100 GWe, the total amount generated in the USA, gives 240 deaths/year. While this study is rather old, no new information has developed in recent years that would increase risk estimates.
12.Report of the President’s Commission on the Accident at Three Mile Island, J.B. Kemeny, chairman. Washington: October 1979; Three Mile Island, A Report to the Commissioners and to the Public, M. Rogovin, director. Washington: January 1980.
13.R. Wilson, S.D. Colome, J.D. Spengler, and D.G. Wilson, Health Effect of Fossil Fuel Burning. Cambridge, MA: Ballinger, 1980; H. Ozkaynak, and J.C. Spengler, “Analyses of Health Effects Resulting from Population Exposure to Acid Precipitation,” Environmental Health Perspectives, 63 (1985), 45.
14.W. Ramsay, The Unpaid Costs of Electrical Energy. Baltimore: Johns Hopkins University Press, 1979.
15.This discussion is based on a group of papers reviewed in B.L. Cohen, “Risk Analysis of Buried Waste from Electricity Generation.” American Journal of Physics, 54 (1986), 38.
16.B.L. Cohen, “The Role of Radon in Comparisons of Environmental Effects of Nuclear Energy, Coal Burning, and Phosphate Mining.” Health Physics, 40 (1981), 19; “Health Effects of Radon from Coal Burning.” Health Physics, 42 (1982), 725.
17.B.L. Cohen, “Catalog of Risks Extended and Updated.” Health Physics, 61 (1991), 317.

source: http://russp.org

An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth’s crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured with a seismometer; a device that also records is called a seismograph. The moment magnitude (or the related and mostly obsolete Richter magnitude) of an earthquake is conventionally reported, with magnitude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale. The depth of the earthquake also matters: the more shallow the earthquake, the more damage to structures (all else being equal). ^[1]

 At the Earth’s surface, earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.

In its most generic sense, the word earthquake is used to describe any seismic event—whether a natural phenomenon or an event caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake’s point of initial rupture is called its focus or hypocenter. The term epicenter refers to the point at ground level directly above the hypocenter.

Naturally occurring earthquakes

Fault types

Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. In the case of transform or convergent type plate boundaries, which form the largest fault surfaces on earth, they move past each other smoothly and aseismically only if there are no irregularities or asperities along the boundary that increase the frictional resistance. Most boundaries do have such asperities and this leads to a form of stick-slip behaviour. Once the boundary has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface, and cracking of the rock, thus causing an earthquake. This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the Elastic-rebound theory. It is estimated that only 10 percent or less of an earthquake’s total energy is radiated as seismic energy. Most of the earthquake’s energy is used to power the earthquake fracture growth or is converted into heat generated by friction. Therefore, earthquakes lower the Earth’s available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth’s deep interior.^[2]

Earthquake fault types

Main article: Fault (geology)

There are three main types of fault that may cause an earthquake: normal, reverse (thrust) and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other; transform boundaries are a particular type of strike-slip fault. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip.

Earthquakes away from plate boundaries

Main article: Intraplate earthquake

Where plate boundaries occur within continental lithosphere, deformation is spread out over a much larger area than the plate boundary itself. In the case of the San Andreas fault continental transform, many earthquakes occur away from the plate boundary and are related to strains developed within the broader zone of deformation caused by major irregularities in the fault trace (e.g., the “Big bend” region). The Northridge earthquake was associated with movement on a blind thrust within such a zone. Another example is the strongly oblique convergent plate boundary between the Arabian and Eurasian plates where it runs through the northwestern part of the Zagros mountains. The deformation associated with this plate boundary is partitioned into nearly pure thrust sense movements perpendicular to the boundary over a wide zone to the southwest and nearly pure strike-slip motion along the Main Recent Fault close to the actual plate boundary itself. This is demonstrated by earthquake focal mechanisms.^[3]

All tectonic plates have internal stress fields caused by their interactions with neighbouring plates and sedimentary loading or unloading (e.g. deglaciation^[4]). These stresses may be sufficient to cause failure along existing fault planes, giving rise to intraplate earthquakes.^[5]

Shallow-focus and deep-focus earthquakes

The majority of tectonic earthquakes originate at the ring of fire in depths not exceeding tens of kilometers. Earthquakes occurring at a depth of less than 70 km are classified as ‘shallow-focus’ earthquakes, while those with a focal-depth between 70 and 300 km are commonly termed ‘mid-focus’ or ‘intermediate-depth’ earthquakes. In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, deep-focus earthquakes may occur at much greater depths (ranging from 300 up to 700 kilometers).^[6] These seismically active areas of subduction are known as Wadati-Benioff zones. Deep-focus earthquakes occur at a depth where the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure.^[7]

Earthquakes and volcanic activity

Earthquakes often occur in volcanic regions and are caused there, both by tectonic faults and the movement of magma in volcanoes. Such earthquakes can serve as an early warning of volcanic eruptions, as during the Mount St. Helens eruption of 1980.^[8] Earthquake swarms can serve as markers for the location of the flowing magma throughout the volcanoes. These swarms can be recorded by seismometers and tiltmeters (a device that measures ground slope) and used as sensors to predict imminent or upcoming eruptions.^[9]

Rupture dynamics

A tectonic earthquake begins by an initial rupture at a point on the fault surface, a process known as nucleation. The scale of the nucleation zone is uncertain, with some evidence, such as the rupture dimensions of the smallest earthquakes, suggesting that it is smaller than 100 m while other evidence, such as a slow component revealed by low-frequency spectra of some earthquakes, suggest that it is larger. The possibility that the nucleation involves some sort of preparation process is supported by the observation that about 40% of earthquakes are preceded by foreshocks. Once the rupture has initiated it begins to propagate along the fault surface. The mechanics of this process are poorly understood, partly because it is difficult to recreate the high sliding velocities in a laboratory. Also the effects of strong ground motion make it very difficult to record information close to a nucleation zone.^[10]

Rupture propagation is generally modelled using a fracture mechanics approach, likening the rupture to a propagating mixed mode shear crack. The rupture velocity is a function of the fracture energy in the volume around the crack tip, increasing with decreasing fracture energy. The velocity of rupture propagation is orders of magnitude faster than the displacement velocity across the fault. Earthquake ruptures typically propagate at velocities that are in the range 70–90 % of the S-wave velocity and this is independent of earthquake size. A small subset of earthquake ruptures appear to have propagated at speeds greater than the S-wave velocity. These supershear earthquakes have all been observed during large strike-slip events. The unusually wide zone of coseismic damage caused by the 2001 Kunlun earthquake has been attributed to the effects of the sonic boom developed in such earthquakes. Some earthquake ruptures travel at unusually low velocities and are referred to as slow earthquakes. A particularly dangerous form of slow earthquake is the tsunami earthquake, observed where the relatively low felt intensities, caused by the slow propagation speed of some great earthquakes, fail to alert the population of the neighbouring coast, as in the 1896 Meiji-Sanriku earthquake.^[10]

Earthquake clusters

Most earthquakes form part of a sequence, related to each other in terms of location and time.^[11] Most earthquake clusters consist of small tremors that cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.^[12]

Aftershocks

Main article: Aftershock

An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock. Aftershocks are formed as the crust around the displaced fault plane adjusts to the effects of the main shock.^[11]

Earthquake swarms

Main article: Earthquake swarm

Earthquake swarms are sequences of earthquakes striking in a specific area within a short period of time. They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notable higher magnitudes than the other. An example of an earthquake swarm is the 2004 activity at Yellowstone National Park.^[13]

Earthquake storms

Main article: Earthquake storm

Sometimes a series of earthquakes occur in a sort of earthquake storm, where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern was observed in the sequence of about a dozen earthquakes that struck the North Anatolian Fault in Turkey in the 20th century and has been inferred for older anomalous clusters of large earthquakes in the Middle East.^[14][15]

Size and frequency of occurrence

There are around 500,000 earthquakes each year. About 100,000 of these can actually be felt.^[16][17] Minor earthquakes occur nearly constantly around the world in places like California and Alaska in the U.S., as well as in Guatemala. Chile, Peru, Indonesia, Iran, Pakistan, the Azores in Portugal, Turkey, New Zealand, Greece, Italy, and Japan, but earthquakes can occur almost anywhere, including New York City, London, and Australia.^[18] Larger earthquakes occur less frequently, the relationship being exponential; for example, roughly ten times as many earthquakes larger than magnitude 4 occur in a particular time period than earthquakes larger than magnitude 5. In the (low seismicity) United Kingdom, for example, it has been calculated that the average recurrences are: an earthquake of 3.7 – 4.6 every year, an earthquake of 4.7 – 5.5 every 10 years, and an earthquake of 5.6 or larger every 100 years.^[19] This is an example of the Gutenberg-Richter law.

The Messina earthquake and tsunami took as many as 200,000 lives on December 28, 1908 in Sicily and Calabria.^[20]

The number of seismic stations has increased from about 350 in 1931 to many thousands today. As a result, many more earthquakes are reported than in the past, but this is because of the vast improvement in instrumentation, rather than an increase in the number of earthquakes. The USGS estimates that, since 1900, there have been an average of 18 major earthquakes (magnitude 7.0-7.9) and one great earthquake (magnitude 8.0 or greater) per year, and that this average has been relatively stable.^[21] In recent years, the number of major earthquakes per year has decreased, though this probably a statistical fluctuation rather than a systematic trend. More detailed statistics on the size and frequency of earthquakes is available from the USGS.^[22]

Most of the world’s earthquakes (90%, and 81% of the largest) take place in the 40,000-km-long, horseshoe-shaped zone called the circum-Pacific seismic belt, known as the Pacific Ring of Fire, which for the most part bounds the Pacific Plate.^[23][24] Massive earthquakes tend to occur along other plate boundaries, too, such as along the Himalayan Mountains.^[25]

With the rapid growth of mega-cities such as Mexico City, Tokyo and Tehran, in areas of high seismic risk, some seismologists are warning that a single quake may claim the lives of up to 3 million people.^[26]

Induced seismicity

Main article: Induced seismicity

While most earthquakes are caused by movement of the Earth’s tectonic plates, human activity can also produce earthquakes. Four main activities contribute to this phenomenon: constructing large dams and buildings, drilling and injecting liquid into wells, and by coal mining and oil drilling.^[27] Perhaps the best known example is the 2008 Sichuan earthquake in China’s Sichuan Province in May; this tremor resulted in 69,227 fatalities and is the 19th deadliest earthquake of all time. The Zipingpu Dam is believed to have fluctuated the pressure of the fault 1,650 feet (503 m) away; this pressure probably increased the power of the earthquake and accelerated the rate of movement for the fault.^[28] The greatest earthquake in Australia’s history was also induced by humanity, through coal mining. The city of Newcastle was built over a large sector of coal mining areas. The earthquake spawned from a fault that reactivated due to the millions of tonnes of rock removed in the mining process.^[29]

Measuring and locating earthquakes

Main article: Seismology

Earthquakes can be recorded by seismometers up to great distances, because seismic waves travel through the whole Earth’s interior. The absolute magnitude of a quake is conventionally reported by numbers on the Moment magnitude scale (formerly Richter scale, magnitude 7 causing serious damage over large areas), whereas the felt magnitude is reported using the modified Mercalli intensity scale (intensity II-XII).

Every tremor produces different types of seismic waves, which travel through rock with different velocities:

• Longitudinal P-waves (shock- or pressure waves)
• Transverse S-waves (both body waves)
• Surface waves—(Rayleigh and Love waves)

Propagation velocity of the seismic waves ranges from approx. 3 km/s up to 13 km/s, depending on the density and elasticity of the medium. In the Earth’s interior the shock- or P waves travel much faster than the S waves (approx. relation 1.7 : 1). The differences in travel time from the epicentre to the observatory are a measure of the distance and can be used to image both sources of quakes and structures within the Earth. Also the depth of the hypocenter can be computed roughly.

In solid rock P-waves travel at about 6 to 7 km per second; the velocity increases within the deep mantle to ~13 km/s. The velocity of S-waves ranges from 2–3 km/s in light sediments and 4–5 km/s in the Earth’s crust up to 7 km/s in the deep mantle. As a consequence, the first waves of a distant earth quake arrive at an observatory via the Earth’s mantle.

Rule of thumb: On the average, the kilometer distance to the earthquake is the number of seconds between the P and S wave times 8.^[30] Slight deviations are caused by inhomogeneities of subsurface structure. By such analyses of seismograms the Earth’s core was located in 1913 by Beno Gutenberg.

Earthquakes are not only categorized by their magnitude but also by the place where they occur. The world is divided into 754 Flinn-Engdahl regions (F-E regions), which are based on political and geographical boundaries as well as seismic activity. More active zones are divided into smaller F-E regions whereas less active zones belong to larger F-E regions.

Effects of earthquakes

1755 copper engraving depicting Lisbon in ruins and in flames after the 1755 Lisbon earthquake, which killed an estimated 60,000 people. A tsunami overwhelms the ships in the harbor.

The effects of earthquakes include, but are not limited to, the following:

Shaking and ground rupture

Shaking and ground rupture are the main effects created by earthquakes, principally resulting in more or less severe damage to buildings and other rigid structures. The severity of the local effects depends on the complex combination of the earthquake magnitude, the distance from the epicenter, and the local geological and geomorphological conditions, which may amplify or reduce wave propagation.^[31] The ground-shaking is measured by ground acceleration.

Specific local geological, geomorphological, and geostructural features can induce high levels of shaking on the ground surface even from low-intensity earthquakes. This effect is called site or local amplification. It is principally due to the transfer of the seismic motion from hard deep soils to soft superficial soils and to effects of seismic energy focalization owing to typical geometrical setting of the deposits.

Ground rupture is a visible breaking and displacement of the Earth’s surface along the trace of the fault, which may be of the order of several metres in the case of major earthquakes. Ground rupture is a major risk for large engineering structures such as dams, bridges and nuclear power stations and requires careful mapping of existing faults to identify any likely to break the ground surface within the life of the structure.^[32]

Landslides and avalanches

Main article: Landslide

Earthquakes, along with severe storms, volcanic activity, coastal wave attack, and wildfires, can produce slope instability leading to landslides, a major geological hazard. Landslide danger may persist while emergency personnel are attempting rescue.^[33]

Fires

Fires of the 1906 San Francisco earthquake

Earthquakes can cause fires by damaging electrical power or gas lines. In the event of water mains rupturing and a loss of pressure, it may also become difficult to stop the spread of a fire once it has started. For example, more deaths in the 1906 San Francisco earthquake were caused by fire than by the earthquake itself.^[34]

Soil liquefaction

Main article: Soil liquefaction

Soil liquefaction occurs when, because of the shaking, water-saturated granular material (such as sand) temporarily loses its strength and transforms from a solid to a liquid. Soil liquefaction may cause rigid structures, like buildings and bridges, to tilt or sink into the liquefied deposits. This can be a devastating effect of earthquakes. For example, in the 1964 Alaska earthquake, soil liquefaction caused many buildings to sink into the ground, eventually collapsing upon themselves.^[35]

Tsunami

Main article: Tsunami

The tsunami of the 2004 Indian Ocean earthquake

Tsunamis are long-wavelength, long-period sea waves produced by the sudden or abrupt movement of large volumes of water. In the open ocean the distance between wave crests can surpass 100 kilometers (62 miles), and the wave periods can vary from five minutes to one hour. Such tsunamis travel 600-800 kilometers per hour (373–497 miles per hour), depending on water depth. Large waves produced by an earthquake or a submarine landslide can overrun nearby coastal areas in a matter of minutes. Tsunamis can also travel thousands of kilometers across open ocean and wreak destruction on far shores hours after the earthquake that generated them.^[36]

Ordinarily, subduction earthquakes under magnitude 7.5 on the Richter scale do not cause tsunamis, although some instances of this have been recorded. Most destructive tsunamis are caused by earthquakes of magnitude 7.5 or more.^[36]

Floods

Main article: Flood

A flood is an overflow of any amount of water that reaches land.^[37] Floods occur usually when the volume of water within a body of water, such as a river or lake, exceeds the total capacity of the formation, and as a result some of the water flows or sits outside of the normal perimeter of the body. However, floods may be secondary effects of earthquakes, if dams are damaged. Earthquakes may cause landslips to dam rivers, which collapse and cause floods.^[38]

The terrain below the Sarez Lake in Tajikistan is in danger of catastrophic flood if the landslide dam formed by the earthquake, known as the Usoi Dam, were to fail during a future earthquake. Impact projections suggest the flood could affect roughly 5 million people.^[39]

Tidal forces

Research work has shown a robust correlation between small tidally induced forces and non-volcanic tremor activity.^{[40][41][42][43]}

Human impacts

Damaged infrastructure, one week after the 2007 Peru earthquake

Earthquakes may lead to disease, lack of basic necessities, loss of life, higher insurance premiums, general property damage, road and bridge damage, and collapse or destabilization (potentially leading to future collapse) of buildings. Earthquakes can also precede volcanic eruptions, which cause further problems; for example, substantial crop damage, as in the “Year Without a Summer” (1816).^[44]

Major earthquakes

Main article: List of earthquakes

One of the most devastating earthquakes in history occurred on 23 January 1556 in the Shaanxi province, China, killing more than 830,000 people (see 1556 Shaanxi earthquake).^[45] Most of the population in the area at the time lived in yaodongs, artificial caves in loess cliffs, many of which collapsed during the catastrophe with great loss of life. The 1976 Tangshan earthquake, with death toll estimated to be between 240,000 to 655,000, is believed to be the largest earthquake of the 20th century by death toll.^[46]

The largest earthquake that has been measured on a seismograph reached 9.5 magnitude, occurring on 22 May 1960.^[16][17] Its epicenter was near Cañete, Chile. The energy released was approximately twice that of the next most powerful earthquake, the Good Friday Earthquake, which was centered in Prince William Sound, Alaska.^[47][48] The ten largest recorded earthquakes have all been megathrust earthquakes; however, of these ten, only the 2004 Indian Ocean earthquake is simultaneously one of the deadliest earthquakes in history.

Earthquakes that caused the greatest loss of life, while powerful, were deadly because of their proximity to either heavily populated areas or the ocean, where earthquakes often create tsunamis that can devastate communities thousands of miles away. Regions most at risk for great loss of life include those where earthquakes are relatively rare but powerful, and poor regions with lax, unenforced, or nonexistent seismic building codes.

Preparation

To predict the likelihood of future seismic activity, geologists and other scientists examine the rock of an area to determine if the rock appears “strained.” Studying the faults of an area to study the buildup time it takes for the fault to build up stress sufficient for an earthquake also serves as an effective prediction technique.^[49] Measurements of the amount of accumulated strain energy on the fault each year, time passed since the last major temblor, and the energy and power of the last earthquake are made.^[49] Together the facts allow scientists to determine how much pressure it takes for the fault to generate an earthquake. Though this method is useful, it has only been implemented on California’s San Andreas Fault.^[49]

Today, there are ways to protect and prepare possible sites of earthquakes from severe damage, through the following processes: earthquake engineering, earthquake preparedness, household seismic safety, seismic retrofit (including special fasteners, materials, and techniques), seismic hazard, mitigation of seismic motion, and earthquake prediction. Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries (US, Japan etc.) and late 1970s for many other parts of the world (Turkey, China etc.),^[50] many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the imminent problem, various research work has been carried out. Furthermore, state-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world – such as the ASCE-SEI 41^[51] and the New Zealand Society for Earthquake Engineering (NZSEE)’s guidelines.^[52]

Notes

1. ^ [1]
2. ^ Spence, William; S. A. Sipkin, G. L. Choy (1989). “Measuring the Size of an Earthquake”. United States Geological Survey. http://earthquake.usgs.gov/learning/topics/measure.php. Retrieved 2006-11-03. 
3. ^ Talebian, M. Jackson, J. 2004. A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran. Geophysical Journal International, 156, pages 506-526
4. ^ Nettles, M.; Ekström, G. �R. (2010). “Glacial Earthquakes in Greenland and Antarctica”. Annual Review of Earth and Planetary Sciences 38: 467. doi:10.1146/annurev-earth-040809-152414.  edit
5. ^ Noson, Qamar, and Thorsen (1988). Washington State Earthquake Hazards: Washington State Department of Natural Resources. Washington Division of Geology and Earth Resources Information Circular 85. 
6. ^ “M7.5 Northern Peru Earthquake of 26 September 2005″ (PDF). USGS. ftp://hazards.cr.usgs.gov/maps/sigeqs/20050926/20050926.pdf. Retrieved 2008-08-01. 
7. ^ Greene, H. W.; Burnley, P. C. (October 26, 1989). “A new self-organizing mechanism for deep-focus earthquakes”. Nature 341: 733–737. doi:10.1038/341733a0. 
8. ^ Foxworthy and Hill (1982). Volcanic Eruptions of 1980 at Mount St. Helens, The First 100 Days: USGS Professional Paper 1249. 
9. ^ Watson, John; Watson, Kathie (January 7, 1998). “Volcanoes and Earthquakes”. United States Geological Survey. http://pubs.usgs.gov/gip/earthq1/volcano.html. Retrieved May 9, 2009. 
10. ^ ^{a b} National Research Council (U.S.). Committee on the Science of Earthquakes (2003). “5. Earthquake Physics and Fault-System Science”. Living on an Active Earth: Perspectives on Earthquake Science. Washington D.C.: National Academies Press. p. 418. ISBN 9780309065627. http://www.nap.edu/openbook.php?record_id=10493&page=282. Retrieved 8 July 2010. 
11. ^ ^{a b} “What are Aftershocks, Foreshocks, and Earthquake Clusters?”. http://earthquake.usgs.gov/eqcenter/step/explain.php. 
12. ^ “Repeating Earthquakes”. United States Geological Survey. January 29, 2009. http://earthquake.usgs.gov/research/parkfield/repeat.php. Retrieved May 11, 2009. 
13. ^ “Earthquake Swarms at Yellowstone”. USGS. http://volcanoes.usgs.gov/yvo/2004/Apr04Swarm.html. Retrieved 2008-09-15. 
14. ^ Amos Nur (2000). “Poseidon’s Horses: Plate Tectonics and Earthquake Storms in the Late Bronze Age Aegean and Eastern Mediterranean”. Journal of Archaeological Science 27: 43–63. doi:10.1006/jasc.1999.0431. ISSN 0305-4403. http://water.stanford.edu/nur/EndBronzeage.pdf. 
15. ^ “Earthquake Storms”. Horizon. 9pm 1 April 2003. http://www.bbc.co.uk/science/horizon/2003/earthquakestorms.shtml. Retrieved 2007-05-02. 
16. ^ ^{a b} “Earthquake Facts”. USGS. http://earthquake.usgs.gov/learn/facts.php. Retrieved 2010-04-25. 
17. ^ ^{a b} Pressler, Margaret Webb (14 April 2010). “More earthquakes than usual? Not really.”. KidsPost (Washington Post: Washington Post): pp. C10. 
18. ^ “Earthquake Hazards Program”. USGS. http://earthquake.usgs.gov/. Retrieved 2006-08-14. 
19. ^ “Seismicity and earthquake hazard in the UK”. Quakes.bgs.ac.uk. http://www.quakes.bgs.ac.uk/hazard/Hazard_UK.htm. Retrieved 2010-08-23. 
20. ^ “Italy’s earthquake history.” BBC News. October 31, 2002.
21. ^ “Common Myths about Earthquakes”. USGS. http://earthquake.usgs.gov/learning/faq.php?categoryID=6&faqID=110. Retrieved 2006-08-14. 
22. ^ “Earthquake Facts and Statistics: Are earthquakes increasing?”. USGS. http://neic.usgs.gov/neis/eqlists/eqstats.html. Retrieved 2006-08-14. 
23. ^ “Historic Earthquakes and Earthquake Statistics: Where do earthquakes occur?”. USGS. http://earthquake.usgs.gov/learning/faq.php?categoryID=11&faqID=95. Retrieved 2006-08-14. 
24. ^ “Visual Glossary – Ring of Fire”. USGS. http://earthquake.usgs.gov/learning/glossary.php?termID=150. Retrieved 2006-08-14. 
25. ^ Jackson, James, “Fatal attraction: living with earthquakes, the growth of villages into megacities, and earthquake vulnerability in the modern world,” Philosophical Transactions of the Royal Society, doi: 10.1098/rsta.2006.1805 Phil. Trans. R. Soc. A 15 August 2006 vol. 364 no. 1845 1911-1925.
26. ^ “Global urban seismic risk.” Cooperative Institute for Research in Environmental Science.
27. ^ Madrigal, Alexis (4 June 2008). “Top 5 Ways to Cause a Man-Made Earthquake”. Wired News (CondéNet). http://blog.wired.com/wiredscience/2008/06/top-5-ways-that.html. Retrieved 2008-06-05. 
28. ^ “How Humans Can Trigger Earthquakes”. National Geographic. February 10, 2009. http://news.nationalgeographic.com/news/2009/02/photogalleries/humans-cause-earthquakes/photo2.html. Retrieved April 24, 2009. 
29. ^ Brendan Trembath (January 9, 2007). “Researcher claims mining triggered 1989 Newcastle earthquake”. Australian Broadcasting Corporation. http://www.abc.net.au/am/content/2007/s1823833.htm. Retrieved April 24, 2009. 
30. ^ “Speed of Sound through the Earth”. Hypertextbook.com. http://hypertextbook.com/facts/2001/PamelaSpiegel.shtml. Retrieved 2010-08-23. 
31. ^ “On Shaky Ground, Association of Bay Area Governments, San Francisco, reports 1995,1998 (updated 2003)”. Abag.ca.gov. http://www.abag.ca.gov/bayarea/eqmaps/doc/contents.html. Retrieved 2010-08-23. 
32. ^ Guidelines for evaluating the hazard of surface fault rupture, California Geological Survey
33. ^ “Natural Hazards – Landslides”. USGS. http://www.usgs.gov/hazards/landslides/. Retrieved 2008-09-15. 
34. ^ “The Great 1906 San Francisco earthquake of 1906″. USGS. http://earthquake.usgs.gov/regional/nca/1906/18april/index.php. Retrieved 2008-09-15. 
35. ^ “Historic Earthquakes -1946 Anchorage Earthquake”. USGS. http://earthquake.usgs.gov/regional/states/events/1964_03_28.php. Retrieved 2008-09-15. 
36. ^ ^{a b} Noson, Qamar, and Thorsen (1988). Washington Division of Geology and Earth Resources Information Circular 85. Washington State Earthquake Hazards. 
37. ^ MSN Encarta Dictionary. Flood. Retrieved on 2006-12-28. Archived 2009-10-31.
38. ^ “Notes on Historical Earthquakes”. British Geological Survey. http://www.quakes.bgs.ac.uk/earthquakes/historical/historical_listing.htm. Retrieved 2008-09-15. 
39. ^ “Fresh alert over Tajik flood threat”. BBC News. 2003-08-03. http://news.bbc.co.uk/2/hi/asia-pacific/3120693.stm. Retrieved 2008-09-15. 
40. ^ Thomas, Amanda M.; Bürgmann, Roland; Nadeau, Robert M. (December 24, 2009). “Tremor-tide correlations and near-lithostatic pore pressure on the deep San Andreas fault”. Nature 462 (7276): pp. 1048–1051. doi:10.1038/nature08654. PMID 20033046. http://www.nature.com/nature/journal/v462/n7276/full/nature08654.html. Retrieved December 29, 2009 
41. ^ “Gezeitenkräfte: Sonne und Mond lassen Kalifornien erzittern” SPIEGEL online, 29.12.2009
42. ^ Tamrazyan, Gurgen P. (1967). “Tide-forming forces and earthquakes”. ICARUS (Elsevier) 7: pp. 59–65 
43. ^ Tamrazyan, Gurgen P. (1968). “Principal Regularities in the Distribution of Major Earthquakes Relative to Solar and Lunar Tides and Other Cosmic Forces”. ICARUS (Elsevier) 9: pp. 574–592 
44. ^ “Facts about The Year Without a Summer”. National Geographic UK. http://www.discoverychannel.co.uk/earth/year_without_summer/facts/index.shtml. 
45. ^ “Earthquakes with 50,000 or More Deaths“. U.S. Geological Survey
46. ^ Spignesi, Stephen J. [2005] (2005). Catastrophe!: The 100 Greatest Disasters of All Time. ISBN 0806525584
47. ^ Kanamori Hiroo. “The Energy Release in Great Earthquakes”. Journal of Geophysical Research. http://www.gps.caltech.edu/uploads/File/People/kanamori/HKjgr77.pdf. Retrieved 2010-10-10. 
48. ^ USGS. “How Much Bigger?”. USGS. http://earthquake.usgs.gov/learn/topics/how_much_bigger.php. Retrieved 2010-10-10. 
49. ^ ^{a b c} Watson, John; Watson, Kathie (October 23, 1997). “Predicting Earthquakes”. http://pubs.usgs.gov/gip/earthq1/predict.html. Retrieved May 9, 2009. 
50. ^ “NZSEE Bulletin 39(2)-June 2006″ (PDF). http://ir.canterbury.ac.nz/bitstream/10092/204/1/12605029_Main.pdf. Retrieved 2010-08-23. 
51. ^ ASCE-SEI 41
52. ^ “Contents” (PDF). http://www.nzsee.org.nz/PUBS/2006AISBEGUIDELINES_Corr_06a.pdf. Retrieved 2010-08-23. 

Source: Wikipedia