The breaking of a single asperity: Analysis of an aftershock of the 1975 Oroville, California, earthquake

Abstract Accelerations and acceleration envelopes of S waves from a small (ML = 3.6) aftershock of the 1975 Oroville, California, earthquake have been interpreted using a dynamic model of the failure of a single, isolated asperity on a fault plane. It is shown that the distinctive characteristics of the asperity radiation are a prolonged, emergent onset followed by a two-sided acceleration pulse. This energetic pulse is radiated at the completion of failure of the asperity. Our purpose is to demonstrate the characteristics of asperity radiation using a specific event as an example rather than a trial and error modeling of this event.