Group A, Poster #069, Tectonic Geodesy
The 2020 Westmorland, California earthquake swarm as aftershocks of a slow slip event sustained by fluid flow
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Poster Presentation
2022 SCEC Annual Meeting, Poster #069, SCEC Contribution #12106 VIEW PDF
ily by the slow slip event resulting in a non-linear expansion. A stress-driven model based on the rate-and-state friction successfully explains the overall spatial and temporal evolution of earthquakes, including the time lag between the onset of the slow slip event and the swarm. Later, a distinct back front and a square root of time expansion of clustered seismicity on the en-echelon structures suggest that fluids helped sustain the swarm. Static stress triggering analysis using Coulomb stress and statistics of interevent times suggest that 45 – 65% of seismicity was driven by the slow slip event, 20 – 35% by inter-earthquake interactions, and 10 – 30% by fluids. Our model also provides constraints on the friction parameter and the pore pressure and suggests that this swarm behaved like an aftershock sequence but with the mainshock replaced by the slow slip event.
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