HR: 11:50h
AN: S12A-07    [Abstracts]
TI: Toward the Rapid Imaging of Large Earthquake Rupture Zones with Teleseismic P-waves
AU: * Walker, K
EM: walker@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Inst. of Oceanography, Univ. of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AU: Shearer, P
EM: pshearer@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Inst. of Oceanography, Univ. of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AU: Ishii, M
EM: mishii@smtp.ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Inst. of Oceanography, Univ. of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AU: Earle, P
EM: pearle@usgs.gov
AF: National Earthquake Information Center, U.S. Geological Survey, 711 Illinois Street, Room 509, Golden, CO 80401-1865 United States
AB: A current bottleneck in the prompt estimation of ground shaking associated with large earthquakes is the determination of the rupture length and geometry, rupture propagation direction, and spatial distribution of seismic moment release. The relative locations of the first-motion hypocenter, the early aftershocks, and the Harvard centroid moment tensor are currently the most rapidly obtained data that are used for this purpose. However, these data are routinely obtained several hours after the earthquake, hours that are critical for hazard response teams and tsunami warning systems, as recently evidenced by the disastrous 2004 Sumatra-Andaman Mw 9.3 earthquake. We are developing a near-realtime back-projection technique to image the fault rupture using only the P wavetrain recorded by broadband seismic stations at teleseismic distances. We demonstrate our approach on two large strike-slip earthquakes (14 November 2001 Kokoxili Mw 7.8 and 3 November 2002 Denali Mw 7.9) and two large subduction zone earthquakes (26 December 2004 Sumatra-Andaman Mw 9.3 and 28 March Sumatra Mw 8.6). The imaged ruptures agree well with the distribution of early aftershocks. The imaged spatial distribution of moment release for the strike-slip events also roughly agrees with depth-integrated slip from published finite slip models. This methodology will be implemented at the National Earthquake Information Center (NEIC), providing the rupture geometry, propagation direction, and spatial distribution of seismic moment release within 20-30 minutes of the onset of large earthquakes.
UR: http://sail.ucsd.edu/~walker/Sumatra_8.7/
DE: 7200 SEISMOLOGY
DE: 7203 Body waves
DE: 7209 Earthquake dynamics (1242)
DE: 7215 Earthquake source observations (1240)
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005