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Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust

We compiled a novel microseismicity catalog for the Central Chile megathrust (29°–35°S), comprising 8,750 earthquakes between April 2014 and December 2018. These events describe a pattern of three trenchward open half‐ellipses, consisting of a continuous, coast‐parallel seismicity band at 30–45 km d...

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Detalles Bibliográficos
Autores principales: Sippl, C., Moreno, M., Benavente, R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9286039/
https://www.ncbi.nlm.nih.gov/pubmed/35865107
http://dx.doi.org/10.1029/2021JB022252
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author Sippl, C.
Moreno, M.
Benavente, R.
author_facet Sippl, C.
Moreno, M.
Benavente, R.
author_sort Sippl, C.
collection PubMed
description We compiled a novel microseismicity catalog for the Central Chile megathrust (29°–35°S), comprising 8,750 earthquakes between April 2014 and December 2018. These events describe a pattern of three trenchward open half‐ellipses, consisting of a continuous, coast‐parallel seismicity band at 30–45 km depth, and narrow elongated seismicity clusters that protrude to the shallow megathrust and separate largely aseismic regions along strike. To test whether these shapes could outline highly coupled regions (“asperities”) on the megathrust, we invert GPS displacement data for interplate locking. The best‐fit locking model does not show good correspondence to seismicity, possibly due to lacking resolution. When we prescribe high locking inside the half‐ellipses, however, we obtain models with similar data fits that are preferred according to the Bayesian Information Criterion (BIC). We thus propose that seismicity on the Central Chile megathrust may outline three adjacent highly coupled regions, two of them located between the rupture areas of the 2010 Maule and the 2015 Illapel earthquakes, a segment of the Chilean margin that may be in a late interseismic stage of the seismic cycle.
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spelling pubmed-92860392022-07-19 Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust Sippl, C. Moreno, M. Benavente, R. J Geophys Res Solid Earth Research Article We compiled a novel microseismicity catalog for the Central Chile megathrust (29°–35°S), comprising 8,750 earthquakes between April 2014 and December 2018. These events describe a pattern of three trenchward open half‐ellipses, consisting of a continuous, coast‐parallel seismicity band at 30–45 km depth, and narrow elongated seismicity clusters that protrude to the shallow megathrust and separate largely aseismic regions along strike. To test whether these shapes could outline highly coupled regions (“asperities”) on the megathrust, we invert GPS displacement data for interplate locking. The best‐fit locking model does not show good correspondence to seismicity, possibly due to lacking resolution. When we prescribe high locking inside the half‐ellipses, however, we obtain models with similar data fits that are preferred according to the Bayesian Information Criterion (BIC). We thus propose that seismicity on the Central Chile megathrust may outline three adjacent highly coupled regions, two of them located between the rupture areas of the 2010 Maule and the 2015 Illapel earthquakes, a segment of the Chilean margin that may be in a late interseismic stage of the seismic cycle. John Wiley and Sons Inc. 2021-11-10 2021-11 /pmc/articles/PMC9286039/ /pubmed/35865107 http://dx.doi.org/10.1029/2021JB022252 Text en © 2021 The Authors. https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Research Article
Sippl, C.
Moreno, M.
Benavente, R.
Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust
title Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust
title_full Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust
title_fullStr Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust
title_full_unstemmed Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust
title_short Microseismicity Appears to Outline Highly Coupled Regions on the Central Chile Megathrust
title_sort microseismicity appears to outline highly coupled regions on the central chile megathrust
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9286039/
https://www.ncbi.nlm.nih.gov/pubmed/35865107
http://dx.doi.org/10.1029/2021JB022252
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