Comparing tide record with fault scenarios

Two sketches show features along a tectonic fault where an earthquake occurred, under two scenarios of fault structure.

Detailed Description

Aside from the amount of slip during the 1906 San Francisco Great Earthquake, we need to specify parameters that describe the geometry of faulting. Two of the cases tested include a tsunami generated from continuous rupture of the San Andreas fault and discontinuous rupture indicated by a new interpretation. The calculated subsidence of the earth's surface for the two cases are shown here. Below each figure we show a section of the tide gauge record (solid line) in comparison with a synthetic record using the assumed source geometry. The tsunami record is consistent with rupture of discontinuous segments of the San Andreas fault along the Golden Gate platform. Using this hydrodynamic model, we test other possibilities such as compound rupture involving nearby faults in addition to the San Andreas and tsunamis generated by cliff failures. Of all the possibilities, discontinuous rupture of the San Andreas (above) seems to best explain the Presidio tide gauge record.

Details

Image Dimensions: 570 x 432

Location Taken: San Francisco, CA, US

Credits

Eric Geist, USGS