Afterslip and Viscoelastic Processes and Their Relation with Seismic Activity: An Example from the Study of the Mw 7.2 El Mayor-Cucapah Earthquake (Mexico)

Adriano Gualandi, & Zhen Liu

Published August 14, 2018, SCEC Contribution #8565, 2018 SCEC Annual Meeting Poster #168

Different aseismic deformation processes perturb the stress field in the brittle crust, and consequently influence the seismic activity. Afterslip and viscoelastic relaxation are usually invoked to explain the observed displacements after a major earthquake. Discriminating between the two is challenging though. We achieve this result by applying a variational Bayesian Independent Component Analysis to the position time series from 125 GPS stations following the Mw 7.2 El Mayor-Cucapah earthquake, 2010 (Mexico). Among the retrieved Independent Components, two are clearly related to post-seismic activity: one is characterized by long relaxation time and broad spatial signature, while the other is concentrated in space and time near the mainshock and largest aftershock events. This separation can help to resolve the modeling tradeoff between these contributions. A comparison with the seismic activity that followed the mainshock shows that weak long-range interactions are likely mediated by viscoelastic relaxation while clustered earthquakes are controlled by afterslip.

Key Words
GPS, post-seismic, afterslip, viscoelastic, variational Bayesian Independent Component Analysis (vbICA)

Citation
Gualandi, A., & Liu, Z. (2018, 08). Afterslip and Viscoelastic Processes and Their Relation with Seismic Activity: An Example from the Study of the Mw 7.2 El Mayor-Cucapah Earthquake (Mexico). Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Stress and Deformation Over Time (SDOT)