The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

The 2015 Gorkha earthquake (M-w 7.8) occurred by thrust faulting on a similar to 150 km long and similar to 70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projectio...

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Autores: Kumar, Ajay, Singh, Shashwat K., Mitra, S., Priestley, K. F., Dayal, Shankar
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2017
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/148100
Acceso en línea:http://hdl.handle.net/10261/148100
Access Level:acceso abierto
Palabra clave:Earthquake source observations
Seismicity and tectonics
Continental margins: convergent
Asia
Crustal structure
GPS measurements
Collision zone
Southern Tibet
Rupture
Slip
Sequence
India
Segmentation
Calibration
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spelling The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan ThrustKumar, AjaySingh, Shashwat K.Mitra, S.Priestley, K. F.Dayal, ShankarEarthquake source observationsSeismicity and tectonicsContinental margins: convergentAsiaCrustal structureGPS measurementsCollision zoneSouthern TibetRuptureSlipSequenceIndiaSegmentationCalibrationThe 2015 Gorkha earthquake (M-w 7.8) occurred by thrust faulting on a similar to 150 km long and similar to 70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projection of teleseismic P-wave and inversion of teleseismic body waves provide constraints on the geometry and kinematics of the main-shock rupture and source mechanism of aftershocks. The main-shock initiated similar to 80 km west of Katmandu, close to the locking line on the MHT and propagated eastwards along similar to 117 degrees. azimuth for a duration of similar to 70 s, with varying rupture velocity on a heterogeneous fault surface. The main-shock has been modelled using four subevents, propagating from west-to-east. The first subevent (0-20 s) ruptured at a velocity of similar to 3.5 km s(-1) on a similar to 6 degrees N dipping flat segment of the MHT with thrust motion. The second subevent (20-35 s) ruptured a similar to 18 degrees. Wdipping lateral ramp on the MHT in oblique thrust motion. The rupture velocity dropped from 3.5 km s(-1) to 2.5 km s(-1), as a result of updip propagation of the rupture. The third subevent (35-50 s) ruptured a similar to 7 degrees. N dipping, eastward flat segment of the MHT with thrust motion and resulted in the largest amplitude arrivals at teleseismic distances. The fourth subevent (50-70 s) occurred by left-lateral strike-slip motion on a steeply dipping transverse fault, at high angle to the MHT and arrested the eastward propagation of the main-shock rupture. Eastward stress build-up following the main-shock resulted in the largest aftershock (M-w 7.3), which occurred on the MHT, immediately east of the main-shock rupture. Source mechanisms of moderate aftershocks reveal stress adjustment at the edges of the main-shock fault, flexural faulting on top of the downgoing Indian Plate and extensional faulting in the hanging wall of the MHT.Peer reviewedOxford University PressConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]201720172017info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/148100reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1093/gji/ggw438Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1481002026-05-22T06:33:51Z
dc.title.none.fl_str_mv The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
title The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
spellingShingle The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
Kumar, Ajay
Earthquake source observations
Seismicity and tectonics
Continental margins: convergent
Asia
Crustal structure
GPS measurements
Collision zone
Southern Tibet
Rupture
Slip
Sequence
India
Segmentation
Calibration
title_short The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
title_full The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
title_fullStr The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
title_full_unstemmed The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
title_sort The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust
dc.creator.none.fl_str_mv Kumar, Ajay
Singh, Shashwat K.
Mitra, S.
Priestley, K. F.
Dayal, Shankar
author Kumar, Ajay
author_facet Kumar, Ajay
Singh, Shashwat K.
Mitra, S.
Priestley, K. F.
Dayal, Shankar
author_role author
author2 Singh, Shashwat K.
Mitra, S.
Priestley, K. F.
Dayal, Shankar
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Earthquake source observations
Seismicity and tectonics
Continental margins: convergent
Asia
Crustal structure
GPS measurements
Collision zone
Southern Tibet
Rupture
Slip
Sequence
India
Segmentation
Calibration
topic Earthquake source observations
Seismicity and tectonics
Continental margins: convergent
Asia
Crustal structure
GPS measurements
Collision zone
Southern Tibet
Rupture
Slip
Sequence
India
Segmentation
Calibration
description The 2015 Gorkha earthquake (M-w 7.8) occurred by thrust faulting on a similar to 150 km long and similar to 70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projection of teleseismic P-wave and inversion of teleseismic body waves provide constraints on the geometry and kinematics of the main-shock rupture and source mechanism of aftershocks. The main-shock initiated similar to 80 km west of Katmandu, close to the locking line on the MHT and propagated eastwards along similar to 117 degrees. azimuth for a duration of similar to 70 s, with varying rupture velocity on a heterogeneous fault surface. The main-shock has been modelled using four subevents, propagating from west-to-east. The first subevent (0-20 s) ruptured at a velocity of similar to 3.5 km s(-1) on a similar to 6 degrees N dipping flat segment of the MHT with thrust motion. The second subevent (20-35 s) ruptured a similar to 18 degrees. Wdipping lateral ramp on the MHT in oblique thrust motion. The rupture velocity dropped from 3.5 km s(-1) to 2.5 km s(-1), as a result of updip propagation of the rupture. The third subevent (35-50 s) ruptured a similar to 7 degrees. N dipping, eastward flat segment of the MHT with thrust motion and resulted in the largest amplitude arrivals at teleseismic distances. The fourth subevent (50-70 s) occurred by left-lateral strike-slip motion on a steeply dipping transverse fault, at high angle to the MHT and arrested the eastward propagation of the main-shock rupture. Eastward stress build-up following the main-shock resulted in the largest aftershock (M-w 7.3), which occurred on the MHT, immediately east of the main-shock rupture. Source mechanisms of moderate aftershocks reveal stress adjustment at the edges of the main-shock fault, flexural faulting on top of the downgoing Indian Plate and extensional faulting in the hanging wall of the MHT.
publishDate 2017
dc.date.none.fl_str_mv 2017
2017
2017
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/10261/148100
url http://hdl.handle.net/10261/148100
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1093/gji/ggw438
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Oxford University Press
publisher.none.fl_str_mv Oxford University Press
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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score 15.811543

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