HR: 09:15h
AN: S11B-04 INVITED     [PDF]
TI: Change in Stress Directions Along the Central Denali Fault, Alaska, After the 2002 Earthquake Sequence
AU: * Ratchkovski, N
EM: natasha@giseis.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775-7320 United States
AB: On the basis of earthquake focal mechanisms, the state of stress along the central Denali fault, Alaska system changed after the 2002 earthquake sequence. Before the earthquake sequence, the maximum stress S1 was at a 60 degree angle with the Denali fault west of the point of its maximum curvature, fault-normal between the fault apex and the Totschunda strand, and at 50 degrees with respect to the Totschunda fault. In the epicentral region, the post-event S1 has rotated counter-clockwise. Along the rest of the rupture zone the sense of rotation is clockwise. The S1 direction became nearly fault-normal along the Totschunda strand. Along the central part of the rupture, S1 is over-rotated from the fault-normal direction by 10 to 35 degrees with the minimum stress S3 being nearly vertical, promoting reverse aftershocks. This could be an indication of dynamic overshoot.
DE: 7215 Earthquake parameters
DE: 7230 Seismicity and seismotectonics
SC: Seismology [S]
MN: 2003 Fall Meeting