Geodetic Constraints on Recent Subduction Earthquakes and Future Seismic Hazards in the Southwestern Coast of Mexico

Abstract

Three major subduction earthquakes occurred on March 20, 2012 (Mw 7.4), February 16, 2018 (Mw 7.2), and June 23, 2020 (Mw 7.4) in the southwestern coast of Mexico, which caused fatalities, casualties, considerable damage, and raised safety concerns about future seismic hazards. We use satellite geodetic observations to invert for the slip distributions of the three events and then investigate their interactions. Coulomb Failure Stress (CFS) induced by their slip both on surrounding thrust and normal faults are calculated. The positive CFS changes, along with the spatial-temporal seismicity evolution, approximate earthquake recurrence rate and interseismic coupling, collectively indicate an increased possibility of a near-future rupture around the areas between the 2018 and 2020 events in Oaxaca. Furthermore, there is a lowered chance of shallow coastal or offshore normal earthquakes but an increased chance of inland normal ruptures.