AGU2020 - Seismotectonics of the Lesser Antilles Subduction Zone
Channel: E.M. van Rijsingen
Date: 2021-01-04

My contribution to the American Geophysical Union (AGU) Fall Meeting of 2020. This was an invited talk in session S028 - The Role of Fluids in Aseismic and Seismic Slip on Faults. 

The results presented here are now peer-reviewed and published in the Journal of Geophysical Research: Solid Earth: 
Inferring Interseismic Coupling along the Lesser Antilles Arc: a Bayesian Approach
by Elenora van Rijsingen, Eric Calais, Romain Jolivet, Jean-Bernard de Chabalier, Jorge Jara, Steeve Symithe, Richard Robertson and Graham Ryan
https://doi.org/10.1029/2020JB020677

Plain language summary:
The Lesser Antilles subduction zone forms the plate boundary where the North‐ and South American plates sink underneath the overlying Caribbean plate. Such downgoing movement typically results in the buildup of stress along the frictional interface between the plates. When these stresses overcome the strength of the plate interface, they can be released through potentially devastating earthquakes. Using measurements from GNSS stations on the islands of the Lesser Antilles, we model strain to determine how coupled the interface is. A high degree of coupling means that large “megathrust” earthquakes are likely, while low coupling means that big events are less likely and/or very rare. Two large earthquakes struck the Lesser Antilles in the 19th century, which have been interpreted to have occurred on the subduction interface. In this work we find a low to very low coupling along the plate interface, which implies that (1) these historical earthquakes are unlikely to have occurred on the subduction interface but rather deeper within the downgoing plate, and (2) large, Tohoku‐like, megathrust earthquakes are unlikely and/or must be very rare in the Lesser Antilles.

For more information and questions, go to:
Personal webpage: https://www.elenoravanrijsingen.com/
Twitter: https://twitter.com/tectonora

I also recommend watching this educational video by IRIS Earthquake Science:
https://www.youtube.com/watch?v=u4c3-6oFAZk&ab_channel=IRISEarthquakeScience