Numerical wave propagation study of the unusual response of Nevados de Chillán volcano to two aftershocks of the 2010 MW = 8.8 Maule earthquake
Date
Authors
Farías, Cristian
Galván, Boris
Galván, Boris
Authors
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Date
Datos de publicación:
10.1016/j.jvolgeores.2019.106735
Keywords
Faulting - Induced Seismicity - Neodymium Compounds - Seismic Waves - Volcanoes - Wave Propagation - Chile Earthquakes - Dynamic Changes - Hydrothermal System - Local Structure - Numerical Wave Propagation - Physical Changes - Stress Transfer - Volumetric Response - Earthquakes - Aftershock - Chile Earthquake 2010 - Earthquake Magnitude - Hydrothermal System - Seismic Wave - Seismicity - Volcanology - Wave Propagation - Bio Bio - Chile - Maule - Nevados De Chillan
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Abstract
In 2012, two large aftershocks of the M<inf>W</inf> = 8.8 Maule, Chile earthquake occurred near the Central Chilean coast. Both events, with magnitudes M<inf>W</inf> = 6.1 and M<inf>W</inf> = 7.1 were located about 200 km away from the volcanic/hydrothermal Nevados de Chillán (NdC) complex. The system responded with a significant increase in seismicity to the M<inf>W</inf> = 6.1 event, and with a reduction in seismicity following the latter, larger M<inf>W</inf> = 7.1 earthquake. To understand the physical changes induced by both earthquakes at the NdC, we set up a numerical wave propagation study. Our results show that these observations likely result from dynamic changes at the NdC complex during the passage of the seismic waves. In the case of the M<inf>W</inf> = 6.1 aftershock, the extensive stress transfer was large enough to induce changes at the hydrothermal system, which could have later led to an increase in fluid-driven seismicity. In the case of the M<inf>W</inf> = 7.1 earthquake, the oblique arrival of seismic waves to the main fault of the NdC due to the M<inf>W</inf> = 7.1 earthquake induced slight compressions at the reservoir and created openings in the main fault, promoting fluid migration, which can explain the reduction in seismicity beneath the main craters of the volcano. Results also show that the geometry of an underlying fault system can influence the volumetric response, suggesting that the role of local structures in earthquake-volcano interactions influence the behavior of triggered systems and should therefore not be disregarded. © 2019 Elsevier B.V., All rights reserved.
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Keywords
Faulting , Induced Seismicity , Neodymium Compounds , Seismic Waves , Volcanoes , Wave Propagation , Chile Earthquakes , Dynamic Changes , Hydrothermal System , Local Structure , Numerical Wave Propagation , Physical Changes , Stress Transfer , Volumetric Response , Earthquakes , Aftershock , Chile Earthquake 2010 , Earthquake Magnitude , Hydrothermal System , Seismic Wave , Seismicity , Volcanology , Wave Propagation , Bio Bio , Chile , Maule , Nevados De Chillan
Citation
10.1016/j.jvolgeores.2019.106735