SGER: Postseismic Response to the M = 7.9 Nov. 3, 2002 Denali Earthquake

Purdue University, West Lafayette IN

Investigators

Abstract

Postseismic Response to the M = 7.9 Nov. 3, 2002 Denali Earthquake This proposal seeks funding for a field effort aimed at measuring the postseismic deformation following the Mw = 7.9 Denali earthquake that occurred on November 3, 2002, on the Denali fault in Alaska. Given the size of this earthquake and its significance for improving our knowledge of postseismic processes and lithospheric rheology, we decided to join a field effort led by the Geophysical Institute, University of Alaska Fairbanks to remeasure campaign GPS benchmarks and install continuous GPS sites. Purdue contributed 3 GPS receivers and sent 3 field operators. The field effort was coordinated by UAF, with the participation of UC Berkeley and the technical support of three UNAVCO engineers. The Alaska Volcano Observatory loaned 8 GPS receivers for this operation. A total of 11 continuous sites have therefore been installed in the area likely to be affected by postseismic deformation. This operation is exploratory and high risk because, at the time we went to the field, we did not know precisely what geophysical signals to expect. However, given the magnitude of the event and its shallow rupture, we knew from other examples that significant postseismic effects were very likely (e.g. 1906, M=8.3, San Francisco earthquake; 1857, M=8, Fort Tejon earthquake; 1946, M=8.2, Nankaido earthquake).