Details of the abstract
|Title of paper
|Magnetotelluric investigations in south of Mexico to better understand the seismic hazard of the area.
|List of authors
|Ruiz-Aguilar, D., Husker, A., Arango-Galván, C., Romo-Jones, J.M., García-Suárez, E., Constable, S.
|CICESE, CALTECH, IGEF-UNAM, CICESE, CICESE, Scripps-UCSD
|As part of a collaborative project, we applied Magnetotellurics in the south area of Mexico to better understand its seismic hazard. In the framework of this NSF funded project, we propose an amphibous magnetotelluric sounding survey coupled with seismotectonic analysis to: (1) Determine differences in coupling/slip regimes in and around the Mexican Tehuantepec seismic gap; (2) Image the Tehuantepec Ridge within the subducted plate to determine its role in the coupling and if it contributes to the break between the Trans-Mexican Volcanic Belt (TMVB) arc system and the Chiapas arc; (3) Image any evidence of fluid infiltration in the Tehuantepec fault. The proposed study analyzes the unusually large Mw8.2 normal fault Tehuantepec earthquake which is downdip of a slab interface that has no recorded earthquakes. The proposed reasons for why the earthquake occurred are that it was due to slab pull below a strongly coupled interface or that it was due to slab bending along a reactivated, possibly fluid-filled and poorly coupled subducted outer rise fault. This study would represent the only physical measurement to directly determine which is correct and determine the link to possible future earthquakes. In this work, we present results of the MT land measurements that were recorded from January to March 2022. We used the long-period LEMI-424 systems that are provided by PASSCAL instrument center, and the MT Time Series were robust processed to estimate the MT transfer functions. A 3D inversion scheme was applied using ModEM and we present the obtained results.
|4.0 Tectonics, Magmatism, Geodynamics