10/11/2017 - What we know? And What we think we know about the Mexican Tectonics?

Information:

12:00 PM - 12:50 PM
Geology 1707

Presented By:
Luis Antonio Domínguez Ramírez - UNAM

Abstract

Recent earthquakes along the Mexican subduction zone challenge our current understanding about where and how the next destructive earthquake will nucleate. For example, the September 7th, 2017 M8.2 Juchitan earthquake ruptured a segment along the coast known as the Tehuantepec Gap, where no strong earthquakes have been reported for more than 100 years. Although the location and magnitude of this event was expected, the focal mechanism revealed a normal interplate event, instead of a megathrust subduction zone earthquake. Few days after this event, and even more unlikely event caused vast damage in Mexico City and nearby populations. A M7.1 earthquake occurred scarcely 170km from the city, coincidentally during the 32 anniversary of the M8.1, 1985 Michoacan Earthquake that caused more than 10,000 casualties according to official records. In the same way, this event had normal focal mechanism, likely due to the bending of the flat segment of the Cocos Plate. Current research, focused on understanding what is the contribution of different seismic and aseismic mechanisms mainly along the Guerrero Gap, the closest aseismic gap to Mexico City. Large slow slip events periodically rupture this area and are suspected to triggered large earthquakes along this segment. Characteristic repeating earthquakes show large variations along the coast, suggesting areas of locking and creeping along the trench. Therefore, the Mexican subduction zone still poses a large amount of uncertainties about how large and moderate earthquakes nucleate. Future research must focus on comprehensive studies beyond the traditional areas of research to better understand the seismic risk along the subduction zone and inner areas. If you want to meet with the presenter, please sign up here.

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