Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data
Abstract The Mw 7.1 Anchorage earthquake on 30 November 2018 beneath the south‐central Alaska is a rare intermediate‐depth event larger than Mw 7 that occurred in a complex subduction region, where the young Yakutat oceanic terrane wedges in the continental‐oceanic plate collisional region between t...
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ftdoajarticles:oai:doaj.org/article:e32781583d184f39a9391c817046481e 2023-05-15T18:44:38+02:00 Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data Ping He Yangmao Wen Yunguo Chen Caijun Xu Kaihua Ding 2020-01-01T00:00:00Z https://doi.org/10.1029/2019EA000924 https://doaj.org/article/e32781583d184f39a9391c817046481e EN eng American Geophysical Union (AGU) https://doi.org/10.1029/2019EA000924 https://doaj.org/toc/2333-5084 2333-5084 doi:10.1029/2019EA000924 https://doaj.org/article/e32781583d184f39a9391c817046481e Earth and Space Science, Vol 7, Iss 1, Pp n/a-n/a (2020) Anchorage earthquake InSAR teleseismic data slip inversion subduction structure Astronomy QB1-991 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.1029/2019EA000924 2022-12-31T03:35:06Z Abstract The Mw 7.1 Anchorage earthquake on 30 November 2018 beneath the south‐central Alaska is a rare intermediate‐depth event larger than Mw 7 that occurred in a complex subduction region, where the young Yakutat oceanic terrane wedges in the continental‐oceanic plate collisional region between the Pacific oceanic plate and the North American plate. We use both ascending and descending Sentinel‐1 satellite Interferometric Synthetic Aperture Radar (InSAR) images to construct the coseismic displacement associated with this earthquake, which shows a nearly circular deformation pattern with a subsidence of ~4 cm in line of sight direction. Combining coseismic GPS data, we determine the focal mechanism of this event dominated by normal faulting with N‐S striking of 186° and westward dipping of 64° by using a uniform slip model. Then we find a preferred slip model with both geodetic data and teleseismic data, suggesting the main slips are concentrated on a depth of 55–75 km. The total released moment of our preferred slip model is 5.32 × 1019 N·m, equivalent to Mw 7.1. The rupture process includes two peaks terminating at about 18 s and indicates a unilateral rupture with its front propagating northwestward direction at an average speed of 2.5 km/s. In comparison with the detailed seismic image in this region, this event just occurred in the Yakutat terrane beneath a low velocity zone, suggesting it was caused by slab tear but not slab boundary breaking and determining the lower boundary of shallow thrust‐slip in the Alaska subduction zone. Article in Journal/Newspaper Yakutat Alaska Directory of Open Access Journals: DOAJ Articles Anchorage Pacific Earth and Space Science 7 1 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Anchorage earthquake InSAR teleseismic data slip inversion subduction structure Astronomy QB1-991 Geology QE1-996.5 |
spellingShingle |
Anchorage earthquake InSAR teleseismic data slip inversion subduction structure Astronomy QB1-991 Geology QE1-996.5 Ping He Yangmao Wen Yunguo Chen Caijun Xu Kaihua Ding Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data |
topic_facet |
Anchorage earthquake InSAR teleseismic data slip inversion subduction structure Astronomy QB1-991 Geology QE1-996.5 |
description |
Abstract The Mw 7.1 Anchorage earthquake on 30 November 2018 beneath the south‐central Alaska is a rare intermediate‐depth event larger than Mw 7 that occurred in a complex subduction region, where the young Yakutat oceanic terrane wedges in the continental‐oceanic plate collisional region between the Pacific oceanic plate and the North American plate. We use both ascending and descending Sentinel‐1 satellite Interferometric Synthetic Aperture Radar (InSAR) images to construct the coseismic displacement associated with this earthquake, which shows a nearly circular deformation pattern with a subsidence of ~4 cm in line of sight direction. Combining coseismic GPS data, we determine the focal mechanism of this event dominated by normal faulting with N‐S striking of 186° and westward dipping of 64° by using a uniform slip model. Then we find a preferred slip model with both geodetic data and teleseismic data, suggesting the main slips are concentrated on a depth of 55–75 km. The total released moment of our preferred slip model is 5.32 × 1019 N·m, equivalent to Mw 7.1. The rupture process includes two peaks terminating at about 18 s and indicates a unilateral rupture with its front propagating northwestward direction at an average speed of 2.5 km/s. In comparison with the detailed seismic image in this region, this event just occurred in the Yakutat terrane beneath a low velocity zone, suggesting it was caused by slab tear but not slab boundary breaking and determining the lower boundary of shallow thrust‐slip in the Alaska subduction zone. |
format |
Article in Journal/Newspaper |
author |
Ping He Yangmao Wen Yunguo Chen Caijun Xu Kaihua Ding |
author_facet |
Ping He Yangmao Wen Yunguo Chen Caijun Xu Kaihua Ding |
author_sort |
Ping He |
title |
Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data |
title_short |
Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data |
title_full |
Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data |
title_fullStr |
Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data |
title_full_unstemmed |
Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data |
title_sort |
coseismic rupture geometry and slip rupture process during the 2018 mw 7.1 anchorage, south‐central alaska earthquake: intraplate normal faulting by slab tear constrained by geodetic and teleseismic data |
publisher |
American Geophysical Union (AGU) |
publishDate |
2020 |
url |
https://doi.org/10.1029/2019EA000924 https://doaj.org/article/e32781583d184f39a9391c817046481e |
geographic |
Anchorage Pacific |
geographic_facet |
Anchorage Pacific |
genre |
Yakutat Alaska |
genre_facet |
Yakutat Alaska |
op_source |
Earth and Space Science, Vol 7, Iss 1, Pp n/a-n/a (2020) |
op_relation |
https://doi.org/10.1029/2019EA000924 https://doaj.org/toc/2333-5084 2333-5084 doi:10.1029/2019EA000924 https://doaj.org/article/e32781583d184f39a9391c817046481e |
op_doi |
https://doi.org/10.1029/2019EA000924 |
container_title |
Earth and Space Science |
container_volume |
7 |
container_issue |
1 |
_version_ |
1766235421286596608 |