1. Geodetic Constraints on Recent Subduction Earthquakes and Future Seismic Hazards in the Southwestern Coast of Mexico.
- Author
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Yu, Chen, Li, Zhenhong, and Song, Chuang
- Subjects
TSUNAMI warning systems ,EARTHQUAKE hazard analysis ,SUBDUCTION ,SEISMOGRAMS ,GEODETIC satellites ,DISPLACEMENT (Mechanics) ,EARTHQUAKE damage - 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. Plain Language Summary: Large earthquakes result in stress changes, which can induce or retard regional seismic activity or even trigger other earthquakes. Therefore, understanding historical and recent earthquakes and their associated stress changes are crucial in the evaluation of future seismic hazards. One of the most popular and intuitive ways to relate past and future events is to calculate the Coulomb stress changes during an earthquake and a failure criterion can be established by considering the geometry of nearby faults and the stress changes induced by past events. This requires a detailed knowledge of the amount and direction of slip by which the main fault has slipped during its past ruptures. In this study, we use geodetic surface displacement measurements to invert for the slip distribution and the interactions of three subsequent subduction earthquakes in the southwestern coast of Mexico. We then evaluate the future seismic hazard of the region by considering Coulomb failure stress changes, spatial‐temporal regional seismic activities, historic earthquake records and approximate earthquake recurrence rate. The results show increased chances of a near‐future reverse rupture around Santa Catarina Juquila, Oaxaca and inland normal ruptures, but a lowered chance of shallow coastal or offshore normal ruptures. Key Points: Slip distribution and interactions of three recent subduction earthquakes in Mexico revealed from radar observationsIncreased probability of a near‐future major earthquake around areas between the 2018 and 2020 events in OaxacaLowered chance of shallow coastal or offshore normal earthquakes but increased chance of inland normal ruptures [ABSTRACT FROM AUTHOR]
- Published
- 2021
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