earthquake science and the l'aquila controversy

Geoffrey  Ba*Research  Associate  ProfessorExxonMobil  Fellow

The  Science  and  Predictability  of  EarthquakesL’Aquila  and  Scien=fic  Responsibility

3:32am

3:32am

6  April,  2009

3:32am

6  April,  2009

9.46  km  beneath  L’Aquila

3:32am

6  April,  2009

9.46  km  beneath  L’Aquila

M5.8

Actual  recording  of  the  2004  Parkfield  Earthquake  downloaded  from  the  USGS  Earthquake  Hazards  Program  web  site

Not  parNcularly  large

*  Online  Earthquake  Catalogue  of  the  USGS

242  quakes  as  large  or  larger  around  the  world  during  2009*

297  deaths

So,  what  is  an  earthquake?

earthquake*rTH.kwāke

Noun1. A  sudden  and  violent  shaking  of  the  ground,  some7mes  causing  great  

destruc7on,  as  a  result  of  movements  of  the  Earth’s  crust,  or...

2. A  great  convulsion  or  upheaval:  “a  poli7cal  earthquake”

*  DefiniNon  according  to  Google,  April  2013

The  L’Aquila  quake  seems  to  qualify  under  both  definiNons

Image  produced  by  Shuxia  Zhang  and  Shuo  Wang  at  the  University  of  Minnesota  SupercompuNng  InsNtute

1mm1mm

Rock  strength  is  finiteElas=c  loading  eventually  causes  failure...

Millions  of  Earthquakes  occur  every  yearMost  too  small  to  detect  by  rou=ne  monitoring

Around  20,000*  measured  and  recorded  every  year  by  the  USGS  

*  Magnitude  4  and  above

Major  earthquakes  are  oaen  followed  by  reports  that  they  were  predicted,  or  at  least  

anNcipated,  but  no  claim  of  a  successful  predicNon  of  a  

major  earthquake  has  survived  close  inquiry

We  understand  how  and  why  they  occur,  so  why  can’t  we  

predict  them?

Where?

Howsevere?When?

Where?

Howsevere?When?

Useful  predic7on  exists  only  in  this  intersec7on  space

Howsevere?When?

Useful  predic7on  exists  only  in  this  intersec7on  spaceA

When?

Useful  predic7on  exists  only  in  this  intersec7on  spaceA

A

Useful  predic7on  exists  only  in  this  intersec7on  spaceA

AD

Useful  predic7on  exists  only  in  this  intersec7on  spaceA

ADProbabilis7c  only

Real  rocks  are  irreducibly  complex

We  can  evaluate  their  average  behaviour,  but  

exactly  which  rock  will  fail  when  is  beyond  us

Earthquake  Hazard  MapPeak  ground  accelera=on  with  a  10%  probability  of  being  exceeded  in  50  years

0.001g  percepNble  by  people0.02g  people  can  lose  their  balance

0.1g  light  property  damage

Earthquake  Hazard  MapPeak  ground  accelera=on  with  a  10%  probability  of  being  exceeded  in  50  years

0.001g  percepNble  by  people0.02g  people  can  lose  their  balance

0.1g  light  property  damage

Can  you  guess  where  

L’Aquila  is?

1300 1400 1500 1600 1700 1800 1900 2000

1315

1349

1452

1501

1646

1703* 17

06

*  Town  destroyed5000  dead

Major  Historical  Earthquakes  at  L’Aquila

2009

1300 1400 1500 1600 1700 1800 1900 2000

1315

1349

1452

1501

1646

1703* 17

06

*  Town  destroyed5000  dead

Major  Historical  Earthquakes  at  L’Aquila

2009

Looking  for  paSerns  in  this,  the  biggest  surprise  is  probably  that  the  2009  quake  took  so  long  to  happen

So  who  thinks  the  L’Aquila  7  were  guilty  of  something  now?

So  who  thinks  the  L’Aquila  7  were  guilty  of  something  now?

I  do...but  maybe  not  what  you  think

h*p://rockysubjects.wordpress.com/2012/10/25/fairy-­‐tales-­‐on-­‐shaky-­‐ground-­‐scienNfic-­‐understanding-­‐

and-­‐the-­‐italian-­‐court-­‐system/

rockysubjects.wordpress.com

Ba+  L’Aquila  Earthquake,  May  2013