Aftershocks Preferentially Occur in Previously Active Areas
Session: Beyond Poisson: Seismic Hazards and Risk Assessment for the Real Earth [Poster]
Type: Poster
Date: 4/19/2021
Presentation Time: 11:30 AM Pacific
Description:
The clearest statistical signal in aftershock locations is that most aftershocks occur close to their mainshocks. More precisely, aftershocks are triggered at distances following a power-law decay in distance (Felzer and Brodsky, 2006). This distance decay kernel is used in Epidemic-type Aftershock Sequence (ETAS) modeling and is typically assumed to be isotropic, even though individual sequences show more clustered aftershock occurrence. The assumption of spatially isotropic triggering kernels can impact the estimation of ETAS parameters themselves, such as biasing the magnitude-productivity term alpha and assigning too much weight to secondary rather than primary (direct) triggering. Here we show that aftershock locations, at all mainshock-aftershock distances, preferentially occur in areas of previous seismicity.
Presenting Author: Morgan T. Page
Student Presenter: No
Authors
Morgan Page Presenting Author Corresponding Author mpage@usgs.gov U.S. Geological Survey |
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Aftershocks Preferentially Occur in Previously Active Areas
Category
Beyond Poisson: Seismic Hazards and Risk Assessment for the Real Earth