Fire following Earthquake Aspects of the Southern San Andreas Fault M w 7.8 Earthquake Scenario

Fire following earthquake (FFE) is a significant problem in California. Potential FFE were examined for the ShakeOut Scenario assuming a M_w 7.8 event on a morning in mid-November, with breezy (10 mph) low humidity conditions. FFE is a nonlinear process whose modeling does not have great precision – in many cases the only clear result is differentiation between a few small fires versus major conflagration. For the scenario, analysis indicates approximately 1,600 ignitions, with the central Los Angeles basin experiencing hundreds of large fires. Estimated loss is hundreds to perhaps a thousand lives, and approximately 200 million sq. ft. of residential and commercial building floor area, corresponding to a loss of perhaps as much as one hundred billion dollars virtually fully insured. Mitigation opportunities include construction of a seismically reliable regional saltwater pumping system to protect central Los Angeles, and automated gas shut-off devices in densely built areas.