The June 2020 Mw 7.4 La Crucecita, March 2012 Mw 7.4 Ometepec and February 2018 Mw 7.2 Pinotepa Earthquakes in Mexico Ruptured Small Patches of the Cocos Megathrust
Abstract
Three earthquakes with Mw 7.2 to 7.4 have ruptured the megathrust beneath Oaxaca in the last 8 years. The megathrust of the Cocos Plate beneath Southern Mexico has major variations in the geometry and behavior. The segment beneath the Mexican state of Oaxaca has relatively frequent magnitude 7-7.5 earthquakes on the shallow part of the megathrust and within the subducting slab, and it also has large aseismic slow-slip events. The recent magnitude 7+ megathrust events in 2012, 2018, and 2020 have been at similar depths between 20 and 25 km near the up-dip edge of the slow-slip zone. We study the ruptures of the 20 March 2012 Mw 7.4 Ometepec earthquake near the Guerrero-Oaxaca border, the16 February 2018 Mw 7.2 Pinotepa earthquake near Pinotepa Nacional in Oaxaca, and the 23 June 2020 Mw 7.4 La Crucecita earthquake beneath southeast Oaxaca that were all megathrust events. The 2012 Ometepec and 2018 Pinotepa earthquake epicenters were located about 45 km apart by the Mexican Servicio Sismológico Nacional (SSN), with the 2020 La Crucecita epicenter about 210 km further east.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMT053.0022F
- Keywords:
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- 1242 Seismic cycle related deformations;
- GEODESY AND GRAVITY;
- 3613 Subduction zone processes;
- MINERALOGY AND PETROLOGY;
- 7240 Subduction zones;
- SEISMOLOGY;
- 8170 Subduction zone processes;
- TECTONOPHYSICS