HR: 0800h
AN: G51C-0862    [Abstracts]
TI: Study of the mechanical properties of faults in the North Anatolian Shear Zone using the InSAR observations of coseismic deformation due to the 1999 Izmit Earthquake (Turkey)
AU: * Hamiel, Y
EM: yarivh@ucsd.edu
AF: IGPP, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0225 United States
AU: Fialko, Y
EM: yfialko@ucsd.edu
AF: IGPP, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0225 United States
AB: We use interferometeric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) observations to investigate the coseismic deformation induced by the 17 August 1999 Mw7.4 Izmit earthquake (Turkey). The InSAR data reveal small surface deformation anomalies away from the Izmit rupture, along nearby faults of the North Anatolian Shear Zone (Mudurnu Valley and Iznik faults). These deformation anomalies were interpreted as being due to retrograde triggered slip along these faults (Wright et al., 2001). We demonstrate that the inferred small-scale deformation is consistent with an elastic response of compliant fault zones to the stress field induced by the earthquake. The existence of such mechanically softened fault zones has been suggested based on field observations and studies of fault zone trapped waves as well as theoretical modeling of the fracturing process. We examine the spatial variations and the mechanical properties of the fault-zone using three-dimensional finite element models. In these models, we include compliant fault zones having various geometries and elastic properties, and apply stress changes deduced from the kinematic slip model of the Izmit earthquake. We find that the inferred fault zones have a characteristic width of a few kilometers, similar to fault zones discovered in the Eastern California Shear Zone using InSAR observations of coseismic deformation due to the 1992 Landers and 1999 Hector Mine Earthquakes. Our results suggest that such damage zones may be quite commonly associated with large crustal faults.
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 8111 Continental tectonics: strike-slip and transform
SC: Geodesy [G]
MN: Fall Meeting 2005