IGPP Seminar Series

Fault Tremor Ignited by Shaking from Distant Great Earthquakes; Examples from the San Andreas Fault System and Vancouver Island.

by Professor John Vidale
University of Washington


Subduction zones have been recognized to tremor (radiate 3-10Hz seismic waves) during episodic slow slip events in several places around the world in the last 5 years. More recently, tremor triggered by and simultaneous with the passage of large surface waves have been glimpsed, as well. We report that this phenomenon is much more widespread than had been recognized. The 2002 Denali and 2004 Sumatran earthquakes strongly shook the west coast, causing tremor to emanate in synchronized pulses from several places under Vancouver Island and at least seven regions deep in the SAF fault system during the passage of the surface waves. Parkfield, California, offered particularly clear recordings due to the intense instrumentation planted to await the "characteristic" earthquake scheduled for the late 1980s. Implications, if they can be deduced in time, will be discussed.
Tuesday, 23 October 2007
3853 Slichter Hall
Refreshments at 3:45 PM
Lecture at 4:00 PM