STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION
The inversion seismic tomography algorithm (ITS) was used to calculate 3D seismic anomalies models for velocities of P- and S-waves in the zone of the Sunda arc, Indonesia. In the area under study, strong earthquakes (M>4.8) are clustered in the zone of high P-wave velocities. Earthquake hypo...
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| Format: | Article |
| Language: | English |
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Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust
2015-09-01
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| Series: | Геодинамика и тектонофизика |
| Subjects: | |
| Online Access: | https://www.gt-crust.ru/jour/article/view/35 |
| _version_ | 1797855794943754240 |
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| author | O. A. Kuchay N. A. Bushenkova A. A. Tataurova |
| author_facet | O. A. Kuchay N. A. Bushenkova A. A. Tataurova |
| author_sort | O. A. Kuchay |
| collection | DOAJ |
| description | The inversion seismic tomography algorithm (ITS) was used to calculate 3D seismic anomalies models for velocities of P- and S-waves in the zone of the Sunda arc, Indonesia. In the area under study, strong earthquakes (M>4.8) are clustered in the zone of high P-wave velocities. Earthquake hypocenters are located in zones of both high and low velocity anomalies of S-waves. The giant Sumatra earthquake (December 26, 2004, Mw=9.0) ruptured the greatest fault length of any recorded earthquake, and the rupture started in the area wherein the sign of P-wave velocity anomalies is abruptly changed. We calculated seismotectonic deformations (STD) from data on mechanisms of 2227 earthquakes recorded from 1977 to 2013, and our calculations show that the STD component, that controls vertical extension of rocks, is most stable through all the depth levels. In the marginal regions at the western and eastern sides of the Sunda arc, the crustal areas (depths from 0 to 35 km) are subject to deformations which sign is opposite to that of deformations in the central part. Besides, at depths from 70 to 150 km beneath the Sumatra earthquake epicentre area, the zone is subject to deformations which sign is opposite to that of deformations in the studied part of the Sunda arc. For earthquakes that may occur in the crust in the Sunda arc in the contact zone of the plates, maximum magnitudes depend on the direction of pressure imposed by the actively subducting plate, which is an additional criteria for determining the limit magnitude for the region under study. |
| first_indexed | 2024-04-09T20:29:52Z |
| format | Article |
| id | doaj.art-38aa270da35f464dbfc01886e716a113 |
| institution | Directory Open Access Journal |
| issn | 2078-502X |
| language | English |
| last_indexed | 2024-04-09T20:29:52Z |
| publishDate | 2015-09-01 |
| publisher | Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust |
| record_format | Article |
| series | Геодинамика и тектонофизика |
| spelling | doaj.art-38aa270da35f464dbfc01886e716a1132023-03-30T20:08:00ZengRussian Academy of Sciences, Siberian Branch, Institute of the Earth's crustГеодинамика и тектонофизика2078-502X2015-09-016110.5800/GT-2015-6-1-017335STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGIONO. A. Kuchay0N. A. Bushenkova1A. A. Tataurova2Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of RAS, Novosibirsk, RussiaTrofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of RAS, Novosibirsk, Russia Novosibirsk State University, Novosibirsk, RussiaNovosibirsk State University, Novosibirsk, RussiaThe inversion seismic tomography algorithm (ITS) was used to calculate 3D seismic anomalies models for velocities of P- and S-waves in the zone of the Sunda arc, Indonesia. In the area under study, strong earthquakes (M>4.8) are clustered in the zone of high P-wave velocities. Earthquake hypocenters are located in zones of both high and low velocity anomalies of S-waves. The giant Sumatra earthquake (December 26, 2004, Mw=9.0) ruptured the greatest fault length of any recorded earthquake, and the rupture started in the area wherein the sign of P-wave velocity anomalies is abruptly changed. We calculated seismotectonic deformations (STD) from data on mechanisms of 2227 earthquakes recorded from 1977 to 2013, and our calculations show that the STD component, that controls vertical extension of rocks, is most stable through all the depth levels. In the marginal regions at the western and eastern sides of the Sunda arc, the crustal areas (depths from 0 to 35 km) are subject to deformations which sign is opposite to that of deformations in the central part. Besides, at depths from 70 to 150 km beneath the Sumatra earthquake epicentre area, the zone is subject to deformations which sign is opposite to that of deformations in the studied part of the Sunda arc. For earthquakes that may occur in the crust in the Sunda arc in the contact zone of the plates, maximum magnitudes depend on the direction of pressure imposed by the actively subducting plate, which is an additional criteria for determining the limit magnitude for the region under study.https://www.gt-crust.ru/jour/article/view/35anomalies of p- and s-wave velocitiesthe sunda arcseismotectonic deformationslimit magnitude |
| spellingShingle | O. A. Kuchay N. A. Bushenkova A. A. Tataurova STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION Геодинамика и тектонофизика anomalies of p- and s-wave velocities the sunda arc seismotectonic deformations limit magnitude |
| title | STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION |
| title_full | STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION |
| title_fullStr | STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION |
| title_full_unstemmed | STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION |
| title_short | STRUCTURE OF THE LITHOSPHERE AND SEISMOTECTONIC DEFORMATIONS IN CONTACT ZONE OF LITHOSPHERIC PLATES IN THE SUMATRA ISLAND REGION |
| title_sort | structure of the lithosphere and seismotectonic deformations in contact zone of lithospheric plates in the sumatra island region |
| topic | anomalies of p- and s-wave velocities the sunda arc seismotectonic deformations limit magnitude |
| url | https://www.gt-crust.ru/jour/article/view/35 |
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