Intermediate-depth earthquakes in southern Spain and Alboran Sea

A striking feature of the seismicity in the Ibero-Maghrebian region is a narrow band of intermediate-depth earthquakes (50 < h < 100 km) beneath the western part of the Alboran Sea, with epicenters following a NNE-SSW alignment. The origin and characteristics of this seismicity are debated, an...

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Autores: López-Sánchez, Carolina, Buforn, Elisa, Cesca, Simone, Lozano, Lucía, Sanz de Galdeano, Carlos, Mattesini, Maurizio, Udías, Agustín, Cantavella, Juan V.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/356933
Acceso en línea:http://hdl.handle.net/10261/356933
Access Level:acceso abierto
Palabra clave:Hypocentral relocations
3D-earth model
Non-linear location
Seismic moment tensor inversion
Alboran Sea
Southern Spain
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spelling Intermediate-depth earthquakes in southern Spain and Alboran SeaLópez-Sánchez, CarolinaBuforn, ElisaCesca, SimoneLozano, LucíaSanz de Galdeano, CarlosMattesini, MaurizioUdías, AgustínCantavella, Juan V.Hypocentral relocations3D-earth modelNon-linear locationSeismic moment tensor inversionAlboran SeaSouthern SpainA striking feature of the seismicity in the Ibero-Maghrebian region is a narrow band of intermediate-depth earthquakes (50 < h < 100 km) beneath the western part of the Alboran Sea, with epicenters following a NNE-SSW alignment. The origin and characteristics of this seismicity are debated, and an accurate analysis of this seismic scenario is provided despite the low to moderate magnitude of these earthquakes. In this study, we collect 20 years of seismic data from permanent and temporary installations and reprocess these data with the aid of advanced seismological techniques, including non-linear probabilistic relocation with a 3D-Earth velocity model and a probabilistic moment tensor inversion scheme, to shed new light on intermediate-depth seismicity in Southern Spain and the Alboran Sea. We relocated 238 intermediate-depth earthquakes (M ≥ 3) using a nonlinear probabilistic approach and a recent regional 3D tomography lithospheric velocity model for the Alboran-Betic Rif Zone. Maximum likelihood hypocenters confirm the NNE-SSW distribution in a depth range between 50 and 100 km, depicting three clusters of epicenters with a seismic gap that may be correlate to the boundary between the sunken slabs of the Iberian and African plates around Gibraltar. We simultaneously determined the focal mechanisms of 25 mb > 3.9 earthquakes using P-waves and moment tensors by fitting body-wave amplitude spectra and waveform cross-correlations. We performed an accurate resolution study by repeating the inversion using different 1-D velocity models. The results show predominant horizontal T axes with a rotation on the direction from NE-SW in southern Spain to E-W near the African coast. The distribution of intermediate-depth earthquakes and their source geometries provide new evidence of the seismotectonic complexity of the region, which is possibly controlled by the stopping or slowing down of subduction.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness (CGL2017-86070-R). We want to thank the Instituto Geográfico Nacional (IGN, doi: https://doi.org/10.7914/sn/es) for providing part of the data. C. L-S also wants to thank the Erasmus+ Program of the Universidad Complutense de Madrid for supporting the internship at the German Research Centre for Geosciences (GFZ) and to the GFZ itself. The authors wish to thank the anonymous reviewer, the reviewer Dr. Maria Mesimeri and the editor Dr. Ramon Carbonell for their valuable comments and suggestions, which allowed us to improve our manuscript.Elsevier BVMinisterio de Economía y Competitividad (España)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2024202420222024info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/356933reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CGL2017-86070-Rhttp://dx.doi.org/10.1016/j.tecto.2022.229238Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3569332026-05-22T06:33:51Z
dc.title.none.fl_str_mv Intermediate-depth earthquakes in southern Spain and Alboran Sea
title Intermediate-depth earthquakes in southern Spain and Alboran Sea
spellingShingle Intermediate-depth earthquakes in southern Spain and Alboran Sea
López-Sánchez, Carolina
Hypocentral relocations
3D-earth model
Non-linear location
Seismic moment tensor inversion
Alboran Sea
Southern Spain
title_short Intermediate-depth earthquakes in southern Spain and Alboran Sea
title_full Intermediate-depth earthquakes in southern Spain and Alboran Sea
title_fullStr Intermediate-depth earthquakes in southern Spain and Alboran Sea
title_full_unstemmed Intermediate-depth earthquakes in southern Spain and Alboran Sea
title_sort Intermediate-depth earthquakes in southern Spain and Alboran Sea
dc.creator.none.fl_str_mv López-Sánchez, Carolina
Buforn, Elisa
Cesca, Simone
Lozano, Lucía
Sanz de Galdeano, Carlos
Mattesini, Maurizio
Udías, Agustín
Cantavella, Juan V.
author López-Sánchez, Carolina
author_facet López-Sánchez, Carolina
Buforn, Elisa
Cesca, Simone
Lozano, Lucía
Sanz de Galdeano, Carlos
Mattesini, Maurizio
Udías, Agustín
Cantavella, Juan V.
author_role author
author2 Buforn, Elisa
Cesca, Simone
Lozano, Lucía
Sanz de Galdeano, Carlos
Mattesini, Maurizio
Udías, Agustín
Cantavella, Juan V.
author2_role author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Ministerio de Economía y Competitividad (España)
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Hypocentral relocations
3D-earth model
Non-linear location
Seismic moment tensor inversion
Alboran Sea
Southern Spain
topic Hypocentral relocations
3D-earth model
Non-linear location
Seismic moment tensor inversion
Alboran Sea
Southern Spain
description A striking feature of the seismicity in the Ibero-Maghrebian region is a narrow band of intermediate-depth earthquakes (50 < h < 100 km) beneath the western part of the Alboran Sea, with epicenters following a NNE-SSW alignment. The origin and characteristics of this seismicity are debated, and an accurate analysis of this seismic scenario is provided despite the low to moderate magnitude of these earthquakes. In this study, we collect 20 years of seismic data from permanent and temporary installations and reprocess these data with the aid of advanced seismological techniques, including non-linear probabilistic relocation with a 3D-Earth velocity model and a probabilistic moment tensor inversion scheme, to shed new light on intermediate-depth seismicity in Southern Spain and the Alboran Sea. We relocated 238 intermediate-depth earthquakes (M ≥ 3) using a nonlinear probabilistic approach and a recent regional 3D tomography lithospheric velocity model for the Alboran-Betic Rif Zone. Maximum likelihood hypocenters confirm the NNE-SSW distribution in a depth range between 50 and 100 km, depicting three clusters of epicenters with a seismic gap that may be correlate to the boundary between the sunken slabs of the Iberian and African plates around Gibraltar. We simultaneously determined the focal mechanisms of 25 mb > 3.9 earthquakes using P-waves and moment tensors by fitting body-wave amplitude spectra and waveform cross-correlations. We performed an accurate resolution study by repeating the inversion using different 1-D velocity models. The results show predominant horizontal T axes with a rotation on the direction from NE-SW in southern Spain to E-W near the African coast. The distribution of intermediate-depth earthquakes and their source geometries provide new evidence of the seismotectonic complexity of the region, which is possibly controlled by the stopping or slowing down of subduction.
publishDate 2022
dc.date.none.fl_str_mv 2022
2024
2024
2024
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/356933
url http://hdl.handle.net/10261/356933
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CGL2017-86070-R
http://dx.doi.org/10.1016/j.tecto.2022.229238
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier BV
publisher.none.fl_str_mv Elsevier BV
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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