Extreme Seismic Events: From Basic Science

to Preventive Disaster Management

Scientia vinces

Alik T. Ismail-Zadeh

GPI-UKA МИТПАН

with contributions of many others …

V. Keilis-Borok (UCLA)A. Soloviev (МИТПАН), V. Sokolov (GPI-UKA),

K. Takeuchi (ICHARM, Tsukuba)

Motivation of the talk

Earthquake risk is increasing globally.

Despite a progress in earthquake prediction, our understanding of earthquakes is not yet

enough to predict them accurately.

There is almost no link between earthquake science and earthquake prediction on the one hand, and

preventive disaster management on the other hand.

Sumatra-Aceh, December 2004 Pakistan, October 2005

EXTREMESEISMICEVENTS

Extreme Seismic Events

Extreme seismic events are a key manifestation of dynamics of the lithosphere, a complex hierarchical nonlinear system evolving from stability to a catastrophe over space and time

Understanding of dynamics of extreme events is most important scientific challenge

From physical understanding of the phenomenon to PSHA, modeling of earthquakes, and accurate earthquake prediction

From sophisticated predictions to prompt information delivery to disaster management authorities to undertake preventive measures

An extreme seismic event is an occurrence that with respect to some class of related occurrences, is either notable, rare,

unique, profound, or otherwise significant in terms of its impacts, effects, or outcomes

Understanding of Extreme Seismic EventsGeneral(i) Advances in seismology, geodesy, nonlinear dynamics of the lithosphere, and geodynamics

(ii) Advances in statistical physics, applied mathematics and computer science

Particularly- Comprehensive information on how active fault systems work and on physics of earthquake rupture

- Estimation of tectonic stress and stress changes

- Modeling of dynamics of lithospheric blocks and faults, earthquakes and fault slip rates

- Modern probabilistic seismic hazard and risk assessment - Advances in earthquake prediction

Understanding of Earthquakes based on Physics of Fault Zones

SAFOD project:New information on

fundamental theories of earthquake mechnaics and on

how stress works in the lithosphere: stress generation

and release © USGS

Understanding of Earthquake Preparation Processes

Coseismic interferogram of the Bam earthquake M=6.5, 26.12.2003

(Jonsson et al., 2004)

San Andreas

Line of sight surface velocity from a stack of radar interferograms spanning a time interval between 1992 to 2000. The observed strain rates confirm

that the SAF is approaching the end of its interseismic recurrence (Fialko, 2005)

Model of lithosphere-mantle dynamics

Modelling of Tectonic Stress and Stress ChangeCoulomb-stress change evaluation

Stein et al.,1997Ismail-Zadeh et al. (2005)

Maximum shear stress evaluation

Vrancea

Catalogs of model seismic events allow to analyse

Spatial-temporal correlation between earthquakes

Earthquake clustering Occurrence of large seismic events Long-range interaction between the events Fault slip rates Mechanism of earthquakes Seismic moment release

Modelling of Earthquakes:Block-and-Fault Dynamics Model

Gabrielov et al. (1990); Soloviev and Ismail-Zadeh (2003)

Tibet-Himalayan region case study

Ismail-Zadeh et al. (2007)

Seismic hazard mapping (e.g. by USGS)Seismic Hazard

Comparison of PGA distribution during the Vrancea earthquake (a: MW = 7.2, August 30, 1986)

and the PSHA results evaluated for two types of site conditions (b: rock and c, d: soil) and for two return periods (c: T = 100 yr and d: T = 475 yr) ( Ismail-Zadeh, Sokolov & Bonjer, 2007)

Modelling of Ground Shakingsimulation and animation courtesy of T. Furumura

Velocities due to fault rupture (1995 Kobe M=6.9 earthquake)

Modelling of Ground Shakingsimulation and animation courtesy of SDSU, UCSD, and San Diego Supercomputing Center

Surface velocity due to hypothesised future rupture of the southern SAF

Predicting Extreme Seismic Events

Prediction of extreme events is necessary for:

- Development of their fundamental theory. This is a current frontier of the basic research (“finding order in chaos”), and

- Protection of population, economy, and environment. Natural disasters became “a threat to civilization survival”. Prediction opens a possibility to reduce the damage by escalation of disaster preparedness.

Advances in earthquake likelihood studies

based on seismicity, geodesy, and structural

geology

SCEC / USGS

Long-Term Forecasting of Large Earthquakes

Intermediate-Term Earthquake Prediction

Courtesy of V. Kossobokov

Courtesy of P. Shebalin

Short-Term (months) Earthquake Prediction

Prediction of Kuril Islands M=8.3 (15.11.2006) and

M=8.2 (13.01.2007) Earthquakes

Courtesy of H. Gupta

Short-Term (days) Earthquake Prediction

Courtesy of J. Zschau

Short-Term (hr-min) Earthquake «Prediction» ?

WHEN SNAKES WAKE UP

Mysterious precursors

Despite the progress in earthquake prediction, the present capability for earthquake prediction is not enough to predict extreme events with

high accuracy!

And how to proceed further?

Predicting Extreme Seismic Events

V. Keilis-Borok K. Aki

Trieste, Italy, 2003

How the huge knowledge on earthquakes and earthquake prediction can assist in mitigation or prevention of tragic consequences of extreme seismic events?

What should scientists do to convince disaster management authorities to mitigate or possibly even to prevent humanitarian disasters caused by earthquakes?

Ismail-Zadeh and Takeuchi (Natural Hazards, 2007)

Without having the scientific awareness raised, no political and governmental actions are possible. Here there is a large room for geoscientists to take responsibility.

If the concern of large earthquakes and tsunamis in the Indian Ocean region was made widely and strongly aware in the local community by local government, schools, media, NGOs etc., the preparedness and other preventive actions might have been put forward.

Public Awareness

Safe Evacuation Route

Appropriate Risk Awareness of Local Communities

Understanding of Hazardous Areas

+Early

Warning

=

Safe Evacuation

Public Awareness

Geoscientists should promote e-education through the Internet (Dunbar, 2007)

Awareness and Education

The societal costs and benefits must be re-examined as well as the efforts to improve public safety.

If about 5 to 10% of the funds, necessary for recovery and rehabilitation after a disaster, would be spent to mitigate an anticipated earthquake, it could in effect save lives, constructions, and other resources.

Preparedness

Scientists can help with the design of emergency management plans and practices.

Seismic hazard and risk maps change with time, specifically in big cities and coastal regions, and there is a need to proceed to georisk monitoring.

Therefore, research on time-dependent hazard, vulnerability and risk is essential to update periodically seismic hazard and risk maps.

Risk ( ) = Hazard Vulnarability Exposed Valuetime

Preparedness

Role of GeoSciencein Preventive Disaster Management

While extreme seismic events and their effects are rare in the experience of individuals (and sometimes even societies), it seems to be the role of geoscientists/seismologists to be the “interpreter” of the experience, thereby reducing the impact of the rarity or “extremeness” of the seismic events.

More observations (GEOSS) and sophisticated models are needed to give us more confidence in our estimates.

At present the role of geoscience is limited by inaccurate predictions of extreme seismic events. But this fact should not push geoscientists to give up the predictions of extreme events.

The scientists should enhance the study on temporal and spatial accurate prediction of extreme events, that is, prediction of the two important parameters for preventive disaster management: "where" and "when".

Role of GeoSciencein Preventive Disaster Management

Geo-science must become a "brain" of the preventive disaster management of extreme seismic events.

Geoscientists must act today, disseminate scientific knowledge on earthquake physics and earthquake prediction possibilities and implement state-of-the-art measures to protect society from rare but recurrent extreme natural catastrophes and humanitarian tradegies.

Otherwise we will witness again and again the tragic aftermaths of earthquake disasters, which could have been avoided.

Conclusion