2009 Annual Meeting: San Gorgonio Pass Region Field Trip
Trip Leaders: Doug Yule and Jon Matti
Location: San Gorgonio Pass
Date: September 13, 2009
This trip will visit sites in the San Gorgonio Pass region where the San Andreas fault appears to disaggregate into a family of irregular and discontinuous right-lateral, reverse, thrust, and oblique-normal faults. Seismological studies also show that crustal deformation here is broadly distributed, primarily on strike-slip and thrust faults at depths of ~5-20 km. Deformation along the San Andreas fault zone in this region sharply contrasts regions to the northwest and southeast where deformation is restricted to a much narrower zone. Despite this complexity, ages of paleoseismic earthquakes from the Pass overlap with records in the Mojave and Coachella Valley regions in support of the controversial notion that a very large earthquake can rupture an ~300-km-long segment of the San Andreas fault. This 'worst-case scenario earthquake' facing southern California provided the basis for the Great Southern California ShakeOut Exercise of November 2008.
Space is limited to 60 students.
