Rock mechanics view of a seismogenic fault zone Scholz, 1988 1

Large shallow earthquakes well imaged by space geodesy Mw 7.3 Landers (California, USA), 1992 Mw 7.4 Izmit (Turkey), 1999 Mw 7.1 Hector Mine (California, USA), 1999 Mw 6.6 Bam (Iran), 2003 Mw 7.9 Wenchuan (China), 2008 Mw 7.0 Haiti, 2010 Mw 7.2 El Mayor-Cucapah (Mexico), 2010 2

M7.3 Landers, 1992 vertical horizontal Fialko et al., JGR 2004 Sdfsdfsd fdsdf Fialko et al., JGR 2004

Mw 7.1 Hector Mine (California, USA), 1999 vertical horizontal Sdfsdfsd fdsdf Fialko et al., GRL 2001 Simons et al., BSSA 2002

Mw 6.6 Bam (Iran), 2003 vertical horizontal Fialko et al., Nature 2005 Sdfsdfsd fdsdf Fialko et al., Nature 2005

April 4, 2010 M7.2 El Mayor (Mexico) earthquake ENVISAT track 84 from ENVISAT and ALOS data

7

triggered slip Wei et al., 2010

Wei, Sandwell and Fialko, JGR 2009 Sdfsdfsd fdsdf Wei, Sandwell and Fialko, JGR 2009

Wei et al., JGR 2009 Sdfsdfsd fdsdf

Sdfsdfsd fdsdf Wei et al., JGR 2009

Effect of a fault damage zone Chester et al., 1993 Chester et al., 2005 13

Effect of a fault damage zone co-Hector Mine Fialko et al., Science, 2002 co-Landers Sdfsdfsd fdsdf Fialko, JGR 2004

Effect of a fault damage zone Sylvain Barbot Barbot et al., JGR 2008 15

Conclusions - Inversions of space geodetic data for slip distribution due to large strike-slip earthquakes reveal “shallow slip deficit” - Reduced near-surface coseismic slip is predicted by models of earthquake cycle on faults with rate-and-state friction; same simulations predict shallow fault creep in the postseismic and interseismic periods InSAR observations do not reveal shallow creep sufficient to relieve the inferred coseismic deficit In the presence of macroscopic compliant zones, the inferred deficit is in fact underestimated Plastic yielding during coseismic slip tempers strain near the fault and may account for at least some of the deficit 16