64 Cordilleran Subduction Zones: Dynamics of Plate Deformation from Megathrust to Mountain Building

Monday, 11 October 2021
8:00 AM - 12:00 PM
Oregon Ballroom 202/203/204 (Hybrid Room)

SEISMIC AND ASEISMIC SLIP BEHAVIOR ALONG CHILEAN SUBDUCTION

Paper number: 64-10
Program: Technical Sessions
Time: 10:40 AM – 11:00 AM

Authors

Abstract

The Chilean subduction margin is characterized by large megathrust earthquakes (Mw > 8.4). These events occur at the average rate of two per century. After 2010 Mw 8.8 Maule megathrust earthquake an important increases in the deployment of seismological and geodesy stations allows us to have almost 10 years of continuous recording data. We use this information to observe in detail the seismic processes of the Chilean subduction, for example: 1) Clusters and swarms occur repeatedly in the same areas; some of them occur periodically and include repeating earthquakes. This seismicity is spatially related to tectonic structures of Nazca plate, 2) Slow slip events have preceded well recorded events (Iquique 2014 and Valparaíso 2017), 3) Seismic active deep (~100 km) interplay before some megathrust earthquakes, 4) Postseismic deformations interplay with other events, 5) Signatures of Non Volcanic Tremors (NVT) begin to find in several zones along Chile. We discuss in detail three zones where these processes have been well recorded: 1) The Central zone where 2010 Mw 8.8 Maule and 2015 Mw 8.3 Illapel earthquakes occurred. 2) The Northern zone where took place the 2014 Mw 8.2 Iquique and 2005 Mw 7.8 Taparacá earthquakes and 3) The North Central zone where the 2020 Atacama earthquakes occurred and where the subduction of Copiapó ridge controls the presence seismic swarms, NVT and slow slip events. Here, we propose that these different processes interact among them speeding up or slowing down the occurrence of megathrust earthquakes. These results provide new information about the processes that generate the great earthquakes in Chile.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-368020

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