HR: 1330h
AN: S12A-0371    [PDF]
TI: Crustal Deformation Associated With the 2002 Denali Fault Earthquake Sequence Observed by SAR Interferometry
AU: * Elliott, J
EM: julie@giseis.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775 United States
AU: Price, E J
EM: evelyn@ig.utexas.edu
AF: Institute for Geophysics, University of Texas at Austin, 4412 Spicewood Springs Road, Austin, TX 78759 United States
AU: Freymueller, J T
EM: jeff@giseis.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775 United States
AB: On October 23, 2002, the Mw 6.7 Nenana Mountain earthquake ruptured a 45-kilometer-long segment of the Denali fault. Eleven days later, November 3, interior Alaska experienced its largest earthquake in recorded history. The Mw 7.9 Denali fault earthquake began 10 kilometers east of the end of the Mw 6.7 rupture and propagated eastward along the Susitna Glacier, Denali, and Totschunda faults. Along the trace of the Nenana Mountain earthquake, aerial surveys found no evidence of surface slip. In contrast, the Denali fault event resulted in a 340-kilometer-long surface rupture and horizontal offsets that reached a maximum of nearly nine meters about 190 kilometers east of the epicenter. Synthetic aperture radar (SAR) interferometry provides an important tool for the study of crustal displacements and fault dynamics. Here we present interferograms for the Nenana Mountain and Denali fault earthquakes constructed from RADARSAT-1 satellite images acquired along the trace of the ruptures. In general, the interferograms show small, discontinuous patches of coherent fringes. Areas within 25 kilometers of the Mw 7.9 earthquake epicenter display no coherence. In the interferograms spanning the Mw 6.7 earthquake, coherent fringes are limited to regions more than 1.5 kilometers away from the fault. Right-lateral motion dominates the deformation signal in all of the interferograms. We compare the displacements revealed by the fringes with those measured at GPS sites located along several transects of the rupture zone. These comparisons allow us to refine slip models for the earthquakes derived from GPS and seismic data.
DE: 1242 Seismic deformations (7205)
DE: 1243 Space geodetic surveys
DE: 6924 Interferometry
DE: 7209 Earthquake dynamics and mechanics
DE: 8107 Continental neotectonics
SC: Seismology [S]
MN: 2003 Fall Meeting