Source models of great earthquakes from ultra low-frequency normal mode data
International audience We present a new earthquake source inversion technique based on normal mode data for the simultaneous determination of the rupture duration, length and moment tensor of large earthquakes with unilateral rupture. We use ultra low-frequency (f <1 mHz) mode singlets and multip...
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ftccsdartic:oai:HAL:insu-03581112v1 2023-12-24T10:23:58+01:00 Source models of great earthquakes from ultra low-frequency normal mode data Lentas, K. Ferreira, A. M. G. Clévédé, E. Roch, Julien Institut de Physique du Globe de Paris (IPGP) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS) Bureau de Recherches Géologiques et Minières (BRGM) (BRGM) 2014 https://insu.hal.science/insu-03581112 https://doi.org/10.1016/j.pepi.2014.05.011 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.1016/j.pepi.2014.05.011 insu-03581112 https://insu.hal.science/insu-03581112 BIBCODE: 2014PEPI.233.41L doi:10.1016/j.pepi.2014.05.011 Physics of the Earth and Planetary Interiors https://insu.hal.science/insu-03581112 Physics of the Earth and Planetary Interiors, 2014, 233, pp.41-67. ⟨10.1016/j.pepi.2014.05.011⟩ [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2014 ftccsdartic https://doi.org/10.1016/j.pepi.2014.05.011 2023-11-26T00:14:18Z International audience We present a new earthquake source inversion technique based on normal mode data for the simultaneous determination of the rupture duration, length and moment tensor of large earthquakes with unilateral rupture. We use ultra low-frequency (f <1 mHz) mode singlets and multiplets which are modelled using Higher Order Perturbation Theory (HOPT), taking into account the Earth’s rotation, ellipticity and lateral heterogeneities. A Monte Carlo exploration of the model space is carried out, enabling the assessment of source parameter tradeoffs and uncertainties. We carry out synthetic tests to investigate errors in the source inversions due to: (i) unmodelled 3-D Earth structure; (ii) noise in the data; (iii) uncertainties in spatio-temporal earthquake location; and, (iv) neglecting the source finiteness in point source inversions. We find that unmodelled 3-D structure is the most serious source of errors for rupture duration and length determinations especially for the lowest magnitude events. The errors in moment magnitude and fault mechanism are generally small, with the rake angle showing systematically larger errors (up to 20°). We then investigate five real thrust earthquakes (M w ⩾8.5): (i) Sumatra-Andaman (26th December 2004); (ii) Nias, Sumatra (28th March 2005); (iii) Bengkulu (12th September 2007); (iv) Tohoku, Japan (11th March 2011); (v) Maule, Chile (27th February 2010); and, (vi) the 24 May 2013 M w 8.3 Okhotsk Sea, Russia, deep (607 km) event. While finite source inversions for rupture length, duration, magnitude and fault mechanism are possible for the Sumatra-Andaman and Tohoku events, for all the other events their lower magnitudes only allow stable point source inversions of mode multiplets. We obtain the first normal mode finite source model for the 2011 Tohoku earthquake, which yields a fault length of 461 km, a rupture duration of 151 s, and hence an average rupture velocity of 3.05 km/s, giving an independent confirmation of the compact nature of this event. For all ... Article in Journal/Newspaper okhotsk sea Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Okhotsk Physics of the Earth and Planetary Interiors 233 41 67 |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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language |
English |
topic |
[SDU]Sciences of the Universe [physics] |
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[SDU]Sciences of the Universe [physics] Lentas, K. Ferreira, A. M. G. Clévédé, E. Roch, Julien Source models of great earthquakes from ultra low-frequency normal mode data |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
International audience We present a new earthquake source inversion technique based on normal mode data for the simultaneous determination of the rupture duration, length and moment tensor of large earthquakes with unilateral rupture. We use ultra low-frequency (f <1 mHz) mode singlets and multiplets which are modelled using Higher Order Perturbation Theory (HOPT), taking into account the Earth’s rotation, ellipticity and lateral heterogeneities. A Monte Carlo exploration of the model space is carried out, enabling the assessment of source parameter tradeoffs and uncertainties. We carry out synthetic tests to investigate errors in the source inversions due to: (i) unmodelled 3-D Earth structure; (ii) noise in the data; (iii) uncertainties in spatio-temporal earthquake location; and, (iv) neglecting the source finiteness in point source inversions. We find that unmodelled 3-D structure is the most serious source of errors for rupture duration and length determinations especially for the lowest magnitude events. The errors in moment magnitude and fault mechanism are generally small, with the rake angle showing systematically larger errors (up to 20°). We then investigate five real thrust earthquakes (M w ⩾8.5): (i) Sumatra-Andaman (26th December 2004); (ii) Nias, Sumatra (28th March 2005); (iii) Bengkulu (12th September 2007); (iv) Tohoku, Japan (11th March 2011); (v) Maule, Chile (27th February 2010); and, (vi) the 24 May 2013 M w 8.3 Okhotsk Sea, Russia, deep (607 km) event. While finite source inversions for rupture length, duration, magnitude and fault mechanism are possible for the Sumatra-Andaman and Tohoku events, for all the other events their lower magnitudes only allow stable point source inversions of mode multiplets. We obtain the first normal mode finite source model for the 2011 Tohoku earthquake, which yields a fault length of 461 km, a rupture duration of 151 s, and hence an average rupture velocity of 3.05 km/s, giving an independent confirmation of the compact nature of this event. For all ... |
author2 |
Institut de Physique du Globe de Paris (IPGP) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS) Bureau de Recherches Géologiques et Minières (BRGM) (BRGM) |
format |
Article in Journal/Newspaper |
author |
Lentas, K. Ferreira, A. M. G. Clévédé, E. Roch, Julien |
author_facet |
Lentas, K. Ferreira, A. M. G. Clévédé, E. Roch, Julien |
author_sort |
Lentas, K. |
title |
Source models of great earthquakes from ultra low-frequency normal mode data |
title_short |
Source models of great earthquakes from ultra low-frequency normal mode data |
title_full |
Source models of great earthquakes from ultra low-frequency normal mode data |
title_fullStr |
Source models of great earthquakes from ultra low-frequency normal mode data |
title_full_unstemmed |
Source models of great earthquakes from ultra low-frequency normal mode data |
title_sort |
source models of great earthquakes from ultra low-frequency normal mode data |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://insu.hal.science/insu-03581112 https://doi.org/10.1016/j.pepi.2014.05.011 |
geographic |
Okhotsk |
geographic_facet |
Okhotsk |
genre |
okhotsk sea |
genre_facet |
okhotsk sea |
op_source |
Physics of the Earth and Planetary Interiors https://insu.hal.science/insu-03581112 Physics of the Earth and Planetary Interiors, 2014, 233, pp.41-67. ⟨10.1016/j.pepi.2014.05.011⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.pepi.2014.05.011 insu-03581112 https://insu.hal.science/insu-03581112 BIBCODE: 2014PEPI.233.41L doi:10.1016/j.pepi.2014.05.011 |
op_doi |
https://doi.org/10.1016/j.pepi.2014.05.011 |
container_title |
Physics of the Earth and Planetary Interiors |
container_volume |
233 |
container_start_page |
41 |
op_container_end_page |
67 |
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1786198330690240512 |