Understanding Extreme Geohazards: The Science of the Disaster Risk Management Cycle

European Science Foundation Conference
November 28 to December 1, 2011, Sant Feliu de Guixols, Spain

Modeling and Predicting Extreme Seismic Events

Alik T. Ismail-Zadeh
Geophysikalisches Institut, Karlsruher Institut f\uuml;r Technologie, Hertzstr. 16, Karlsruhe 76187, GERMANY;
International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Profsoyuznaya str. 84/32, Moscow 117997, RUSSIA;
Institut de Physique du Globe de Paris, 1 rue Jussieu, Paris 75252, FRANCE

Extreme seismic events are manifestations of complex behavior of the lithosphere structured as a hierarchical system of blocks of different sizes. Driven by mantle convection these lithospheric blocks are involved into relative movement, resulting in stress localization and earthquakes. I shall discuss a quantitative approach to simulation of earthquakes in models of fault dynamics, which reproduces basic features of the observed seismicity (like the Gutenberg-Richter law, clustering of earthquakes, occurrence of extreme seismic events, aftershocks and foreshocks). The models provide a link between geodynamical processes and seismicity, allow studying the influence of fault network properties (e.g., fragmentation of the lithosphere into blocks, the block geometry and movement, direction of driving forces) on seismic patterns and seismic cycles, and assist, in a broader sense, in earthquake forecast modeling. Some aspects of predictability of larges earthquakes will be also discussed.