Publication Date:
2004-12-01
Description:
On 3 November 2002, a Mw 7.9 earthquake, the largest continental strike-slip earthquake in North America since the 1857 Fort Tejon, California, event, occurred in central Alaska. The earthquake began with reverse faulting on a ∼40-km extent of the previously unknown Susitna Glacier fault, but rupture transferred eastward to the right-lateral Denali fault and continued for over 200 km, finally transferring to rupture ∼70 km of the Totschunda fault. This large, complex event we term the Denali fault earthquake (dfe), after the major crustal fault that carried most of the displacement. The initiation of the rupture, the Susitna Glacier fault, is in a remote region of central Alaska that under normal circumstances is sparsely instrumented. On 23 October of that year, however, a large earthquake of Mw 6.7, referred to as the Nenana Mountain earthquake (nme), occurred only 22 km to the west of the dfe epicenter. The nme, in hindsight recognized as a foreshock to the dfe, prompted deployment of a temporary network by the Alaska Earthquake Information Center (aeic). Hence, the area was under significantly enhanced seismic surveillance at the time of the dfe, 10 days later, which was further augmented by the addition of 19 more stations following the dfe mainshock. As a result, high-quality data were available in the near field, providing enhanced coverage for aftershock activity from the Susitna Glacier fault initiation point, along the Denali fault as far as the western portion of the Totschunda fault, to augment regional and teleseismic data for this sequence...
Print ISSN:
0037-1106
Electronic ISSN:
1943-3573
Topics:
Geosciences
,
Physics
