← Back to Sessions

Modeling Coseismic Slip and Afterslip of the 2020 Mw6.5 Monte Cristo Range (Nevada) Earthquake Using InSAR and GPS

Session: Intermountain West Earthquakes in the Spring of 2020 II

Type: Oral

Date: 4/20/2021

Presentation Time: 06:15 PM Pacific

Description: 

The 15^th May 2020 M_w6.5 Monte Cristo range, Nevada earthquake occurred in the Mina deflection step-over region of the eastern California shear zone (ECSZ) – Walker Lane Belt (WLB). The strike-slip earthquake ruptured ENE -striking fault(s) with a majorly left-lateral slip mechanism. Here we use InSAR and GPS to map the coseismic and early postseismic (four months) surface displacements associated with the earthquake in an effort to model the coseismic slip and afterslip. We use Bayesian inference to estimate the fault location, fault geometry and spatially-variable slip simultaneously from the coseismic surface displacements considering two cases: single planar fault solution (SPF), two planar faults solution (TPF). We also use a priori fault surface trace from sharp discontinuities in the postseismic surface displacement time-series. The maximum a posteriori (MAP) solution for the SPF case shows a maximum slip of ~1.2 m left-lateral slip at ~10 km depth on a 60° southward dipping fault. In comparison, the MAP solution for TPF case shows an additional nearly vertical E-W striking fault plane, which is east of the planar fault estimated in the SPF case. The dominant slip asperity in both scenarios extends from ~3-12 km depth and tapers to zero slip at the surface where coseismic interferograms remain coherent. From our postseismic time series, we infer shallow afterslip when inverting for slip onto the fault solutions derived from our coseismic analysis. The preliminary results show a cumulative shallow afterslip of about >50 cm (~45% of maximum coseismic slip) in the four months after the earthquake. The rupture's inability to reach the surface but aseismically slip at shallow depths may indicate variation in the fault plane's frictional properties.

Presenting Author: Rishabh Dutta

Student Presenter: No

Authors