Mid-Term Review Meeting, February 13-14, Tutzing Seismic wave Propagation and Imaging in Complex media: a European network Local scale group Responsable: Martin Mai, ETH Zürich Speaker: Raoul Madariaga Senior researcher Ecole Normale Supérieure Paris

Mid-Term Review Meeting, February 13-14, Tutzing Earthquake seismology Fault model Rupture propagation model Wave propagation model Kinematics Dynamics Modelling Propagation Direct Inverse

Mid-Term Review Meeting, February 13-14, Tutzing. BB Seismic waves Hifi Seismic waves Different scales in earthquake dynamics Macroscale Mesoscale Microscale Steady state mechanics vrvr (< 0.3 Hz  5 km) (>0.5 Hz  <2 km) (non-radiative) ( ~ 100 m) This hierarchy of problems was proposed by Kostrov’s

Mid-Term Review Meeting, February 13-14, Tutzing Challenges in macroscale Kinematics : Are inversions realistic? -> Don’t ask! Are they stable? -> Blind Test Dynamics : How do we set up kinematic inversions that are compatible with dynamics ? Both : How to extend the inversions beyond 0.3 Hz, so that they are useful in engineering ? How to interface with GPS, interferometry and geology?

Mid-Term Review Meeting, February 13-14, Tutzing Earthquakes as dynamic shear ruptures Preexisting Fault system in the Mojave desert Rupture modelled on the complex fault system determined from Geology, Geodesy and Seismology Epicenter

Mid-Term Review Meeting, February 13-14, Tutzing Kinematic vs dynamic modelling Peyrat Olsen Madariaga 2001 Wald and Heaton 1994 Landers 28 June 1992

Mid-Term Review Meeting, February 13-14, Tutzing Model B Model E The « smooth » fault model develops supershear shocks The « rough » fault models produces subshear ruptures Why? Detailed energy balance Two attempts to model the Izmit Earthquake Super shear shock Aochi, Fuyama, Madariaga, 2003

Mid-Term Review Meeting, February 13-14, Tutzing vrvr A simple shear crack (earthquake) moving at fast speed Local energy balance GcGc UU DcDc slip friction iniini E s =  U - G c

Mid-Term Review Meeting, February 13-14, Tutzing Mesoscale: Compare a complex fault to a flat one Velocity z Stress  zy Stress  zx Rupture front Residual stresses S waves Slow rupture Madariaga and Ampuero, AGU 05

Mid-Term Review Meeting, February 13-14, Tutzing Outlook for Next 2 years Earthquake seismology progresses as earthquake recording and data availability improves Kinematics: Improvement of wave propagation, methodology and structure (Bonnefoy, Oprsal, Tapia) Kinematics inversion: Compare linear and non- linear techniques. (Holden, Festa) Dynamic inversion: Do it! Let it become the norm rather than the exception. (DiCarli, Burjanek) Mesocale : Understand the generation of high frequencies and EQ energy balance Microscale: See Pablo Ampuero’s presentation