A Short Story About Earthquakes Ein kurzer Vortrag über Erdbeben Wolfgang Rattay Reuters BBC Kurt Decker Universität Wien Department für Geodynamik und Sedimentologie
The short sumary of a short story What causes an earthquake? Are earthquakes more frequent today than they were in the past? Are earthquakes predictable? Magnitude or intensity - what is useful for planning rescue missions? Where to get real-time data for the planning and preparation of rescue missions?
SHARE (Basili et al., 2013)
What causes an earthquake? How does it work? A very short introduction to earthquake physics
M = 6.4 Hualien (Taiwan), 6. Februar 2018 M = 6.2 Norcia-Amatrice (IT), 15. November 2016 M = 7.1 Christchurch (NZ), 4. September 2010 M = 7.2 Baja California (USA), 4. April 2010
Earthquake physics Frictional plasticity / Elastisch-Reibungsplastisch Elastic Rebound Model (Benioff, 1964) (Baice & Byerlee, 1966) Rate and state variable friction / Reibungsstabilitätsregime: the Dietrich-Ruina or Slowness Law t = [m 0 + a ln (V/V 0 ) + b ln (V 0 q/l)] s t Sheastress s Effective normal stress V Slip velocity V 0 Reference velocity m 0 Static friction L Slip distance q State variable: dq / dt = 1 qv/l a, b Material-dependent constants
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Coseismic deformation Seconds - minutes 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Postseismic deformation Weeks - months 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Interseismic deformation 10² - 10³ years 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava Coseismic deformation Seconds - minutes 1-2 mm / year
The active Vienna Basin Fault between the city of Vienna and Bratislava t = [m 0 + a ln (V/V 0 ) + b ln (V 0 q/l)] s Postseismic deformation Weeks - months 1-2 mm / year
Are earthquakes predictable? t = [m 0 + a ln (V/V 0 ) + b ln (V 0 q/l)] s No physics are too complicated and not (yet) properly understood
Are earthquake probabilities predictable? Earthquake hazard maps and their limitations
GSHAP (Giardini, 1999)
Probing the predictions of hazard maps GSHAP (Giardini, 1999) Wyss & Rosset, Nat. Hazards, 2013: Intensities reported for the last 60 earthquakes with M 7.5 were all significantly larger than expected, based on the hazard map (by 2.3 intensity units for the 12 deadliest earthquakes).
Probing the predictions of hazard maps Stein et al., 2012 2008 Wenchuan, M = 7.9 84.000 victims, >300.000 injured USGS seismic hazard map prior to the earthquake
Probing the predictions of hazard maps Hazard map before GSHAP, 1999 Stein et al., 2012 2010 Port-Au-Prince (Haiti) M = 7.1 159.000 victims, >250.000 buildings destroyed and after.
Probing the predictions of hazard maps 2003 Boumardés M = 6.8, 2.300 victims Stein et al., 2012 2004 Marocco M = 6.4, 600 victims, 15.000 displaced
2001 Gujarat, India, M = 7.6 2003 Bam, Iran, M = 6.6 2003 Boumerdés, Algeria, M = 6.8 2008 Wenchuan, China, M = 7.9 ASAMPSA_E Technical Workshop, 08-12 September 2014 / Page 28
Are earthquake probabilities predictable? Yes, but many earthquake hazard maps do a bad job; and
Earthquakes on the North Anatolian Fault Izmit, 6. August 1999, M = 7.4 18.000 victims, 48.000 injured
The conditional probability of an earthquake on the North Anatolian Fault next to Instanbul
M = 7.4 Izmit (Turky), 6. August 1999 M = 7.4 Izmit (Turky), 6. August 1999 M = 7.4 Izmit (Turky), 6. August 1999 M = 7.4 Izmit (Turky), 6. August 1999
The conditional probability of an earthquake on the North Anatolian Fault next to Instanbul
The conditional probability of an earthquake on the North Anatolian Fault next to Instanbul
Magnitude or intensity what is useful for planning rescue missions? Earthquake Magnitude M = log 10 A/T + F(D,h) + C
Earthquake Intensity EMS-98 European Macroseismic Scale Grünthal et al., 1998 I - VI VII VIII IX X XI XII No (serious) damage Damaging Heavily damaging Destructive Very destructive Devastating Completely devastating https://www.gfz-potsdam.de/en/section/seismic-hazard-and-riskdynamics/data-products-services/ems-98-europeanmacroseismic-scale/
Vulnerabilty classes Damage grade A Adobe, earth bricks 1 B Unreinforced, no RC floors 2 C D Unreinforced, RC floors Reinforced 3 4 5
Intensity VIII many few many few few Grünthal, 1998
Intensity IX many few many few many few Grünthal, 1998
Izmit (Turkey), 6. August 1999 M = 7.4 17.000 victims
Kobe (Japan), 17. January 1995, M = 7.2 4.500 victims
What type of measure of the strength of an eartquake ( magnitude, intensity ) is useful for planning rescue? X Earthquake intensity provides straightforward information on damage
Are earthquakes more frequent today than they were in the past? Introducing the Gutenberg-Richter frequency relation
Are earthquakes getting more frequent? Total losses and insured losses caused by natural desasters Münchner Rück Topics Geo 2016
Are earthquakes getting more frequent? Number of damaging natural desasters events Münchner Rück Topics Geo 2016
Are earthquakes getting more frequent? How frequent are earthquakes? 1976-2005 Global CMT Catalogue Gutenberg-Richter magnitude-frequency relationship describing self-organized criticality
Are earthquakes getting more frequent? How frequent are earthquakes? 1976-2005 Global CMT Catalogue Gutenberg-Richter magnitude-frequency relationship describing self-organized criticality
How frequent are earthquakes?
Are earthquakes more frequent today than they were in the past? No - losses and numbers of victims increase because more and more people and values are exposed to risk
Where to get real-time data for the planning and preparation of rescue missions? Some on-line sources
Sources for real-time information European-Mediterranean Seismological Centre (EMSC) U.S. Geological Survey Last 24 hours before yesterday Last 24 hours before yesterday https://earthquake.usgs.gov/earthquake/ https://www.emsc-csem.org/
https://earthquake.usgs.gov/data/shakemap/ 2018-06-22 (yesterday) ShakeMaps provide near-real-time maps of shaking intensity. The maps are used by federal, state, and local organizations, for postearthquake response and recovery, as well as for preparedness exercises and disaster planning.
https://earthquake.usgs.gov/data/shakemap/ 2018-06-22 (yesterday)
https://earthquake.usgs.gov/data/shakemap/ ShakeMap for 1999 Izmit M = 7.4
Izmit region on Google Earth
https://earthquake.usgs.gov/scenarios//
The short sumary of a short story Earthquakes are caused by tectonic faults Earthquake physics are too complex for predictions but they prove that earthquakes do not get more frequent Hazard maps provide information on earthquake probability However, hazard maps frequently fail Earthquake intensity is most meaningful for desaster mitigation Real-time information found in ShakeMaps