Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves

Abstract The Mw8.4 Illapel earthquake occurred on 16 September was the largest global event in 2015. This earthquake was not unexpected because the hypocenter was located in a seismic gap of the Peru‐Chile subduction zone. However, the source model derived from 3‐D spectral‐element inversion of tele...

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Main Authors: Shiann‐Jong Lee, Te‐Yang Yeh, Tzu‐Chi Lin, Yen‐Yu Lin, Teh‐Ru Alex Song, Bor‐Shouh Huang
Format: Article
Language:English
Published: Wiley 2016-05-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL068843
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author Shiann‐Jong Lee
Te‐Yang Yeh
Tzu‐Chi Lin
Yen‐Yu Lin
Teh‐Ru Alex Song
Bor‐Shouh Huang
author_facet Shiann‐Jong Lee
Te‐Yang Yeh
Tzu‐Chi Lin
Yen‐Yu Lin
Teh‐Ru Alex Song
Bor‐Shouh Huang
author_sort Shiann‐Jong Lee
collection DOAJ
description Abstract The Mw8.4 Illapel earthquake occurred on 16 September was the largest global event in 2015. This earthquake was not unexpected because the hypocenter was located in a seismic gap of the Peru‐Chile subduction zone. However, the source model derived from 3‐D spectral‐element inversion of teleseismic waves reveals a distinct two‐stage rupture process with completely different slip characteristics as a composite megathrust event. The two stages were temporally separated. Rupture in the first stage, with a moment magnitude of Mw8.32, built up energetically from the deeper locked zone and propagated in the updip direction toward the trench. Subsequently, the rupture of the second stage, with a magnitude of Mw8.08, mainly occurred in the shallow subduction zone with atypical repeating slip behavior. The unique spatial‐temporal rupture evolution presented in this source model is key to further in‐depth studies of earthquake physics and source dynamics in subduction systems.
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issn 0094-8276
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series Geophysical Research Letters
spelling doaj-art-ee505d6870c846d09244c82223cb979d2025-08-20T02:31:41ZengWileyGeophysical Research Letters0094-82761944-80072016-05-0143104979498510.1002/2016GL068843Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic wavesShiann‐Jong Lee0Te‐Yang Yeh1Tzu‐Chi Lin2Yen‐Yu Lin3Teh‐Ru Alex Song4Bor‐Shouh Huang5Institute of Earth Sciences Academia Sinica Taipei TaiwanInstitute of Earth Sciences Academia Sinica Taipei TaiwanInstitute of Geosciences National Taiwan University Taipei TaiwanInstitute of Earth Sciences Academia Sinica Taipei TaiwanDepartment of Earth Sciences University College London London UKInstitute of Earth Sciences Academia Sinica Taipei TaiwanAbstract The Mw8.4 Illapel earthquake occurred on 16 September was the largest global event in 2015. This earthquake was not unexpected because the hypocenter was located in a seismic gap of the Peru‐Chile subduction zone. However, the source model derived from 3‐D spectral‐element inversion of teleseismic waves reveals a distinct two‐stage rupture process with completely different slip characteristics as a composite megathrust event. The two stages were temporally separated. Rupture in the first stage, with a moment magnitude of Mw8.32, built up energetically from the deeper locked zone and propagated in the updip direction toward the trench. Subsequently, the rupture of the second stage, with a magnitude of Mw8.08, mainly occurred in the shallow subduction zone with atypical repeating slip behavior. The unique spatial‐temporal rupture evolution presented in this source model is key to further in‐depth studies of earthquake physics and source dynamics in subduction systems.https://doi.org/10.1002/2016GL0688432015 Illapel earthquakesource rupture processseismic wave propagationtwo‐stage megathrustsubduction zone
spellingShingle Shiann‐Jong Lee
Te‐Yang Yeh
Tzu‐Chi Lin
Yen‐Yu Lin
Teh‐Ru Alex Song
Bor‐Shouh Huang
Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves
Geophysical Research Letters
2015 Illapel earthquake
source rupture process
seismic wave propagation
two‐stage megathrust
subduction zone
title Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves
title_full Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves
title_fullStr Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves
title_full_unstemmed Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves
title_short Two‐stage composite megathrust rupture of the 2015 Mw8.4 Illapel, Chile, earthquake identified by spectral‐element inversion of teleseismic waves
title_sort two stage composite megathrust rupture of the 2015 mw8 4 illapel chile earthquake identified by spectral element inversion of teleseismic waves
topic 2015 Illapel earthquake
source rupture process
seismic wave propagation
two‐stage megathrust
subduction zone
url https://doi.org/10.1002/2016GL068843
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