Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment.
[1] We investigate the tectonics of the South Shetland Trench and Bransfield Strait by performing a detailed study of local seismicity. During 1997-1999 we deployed seven land seismometers and 14 ocean bottom seismometers in the South Shetland Island region. The data we obtained indicate a high leve...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.1075.6667 2023-05-15T15:46:01+02:00 Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. Stacey D Robertson Maurice Douglas A Wiens Patrick J Shore Emilio Vera Leroy M Dorman Robertson Maurice S D D A Wiens P J Shore E Vera Seismicity L M Dorman The Pennsylvania State University CiteSeerX Archives 2003 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1075.6667 http://epsc.wustl.edu/seismology/doug/wp-content/uploads/2013/06/robertson_jgr_2003.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1075.6667 http://epsc.wustl.edu/seismology/doug/wp-content/uploads/2013/06/robertson_jgr_2003.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://epsc.wustl.edu/seismology/doug/wp-content/uploads/2013/06/robertson_jgr_2003.pdf text 2003 ftciteseerx 2020-04-26T00:29:53Z [1] We investigate the tectonics of the South Shetland Trench and Bransfield Strait by performing a detailed study of local seismicity. During 1997-1999 we deployed seven land seismometers and 14 ocean bottom seismometers in the South Shetland Island region. The data we obtained indicate a high level of local seismicity (m b 2-5), and we accurately located $150 earthquakes. Many of the earthquakes occur at locations and depths indicative of ongoing subduction in the South Shetland trench. A focal mechanism for the largest event in the forearc indicates shallow angle thrusting. The maximum depth of seismicity is $65 km, but the majority of the events are shallower than 30 km. These seismic results are consistent with recent magnetic, GPS, and multichannel seismic reflection data that suggest continued subduction at a very slow rate. The South Shetland trench thus represents an extreme end-member of hot subduction resulting from slow convergence of young lithosphere, and the absence of intermediate depth earthquakes is consistent with thermal assimilation of the slab at shallow depths. We have located many earthquakes associated with volcanism and rifting in Bransfield Strait. A swarm of events near a submarine volcano suggests current magmatic activity. A normal faulting focal mechanism in the northeastern part of the strait gives evidence of extension. Earthquakes associated with rifting in the northeastern portion of the strait are clustered along wellestablished rifts, but the seismicity is much more diffuse to the southwest. This observation is consistent with other evidence that extension has propagated from northeast to southwest. Text Bransfield Strait South Shetland Islands Unknown Bransfield Strait South Shetland Islands South Shetland Trench ENVELOPE(-59.500,-59.500,-61.000,-61.000) |
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Open Polar |
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Unknown |
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ftciteseerx |
language |
English |
description |
[1] We investigate the tectonics of the South Shetland Trench and Bransfield Strait by performing a detailed study of local seismicity. During 1997-1999 we deployed seven land seismometers and 14 ocean bottom seismometers in the South Shetland Island region. The data we obtained indicate a high level of local seismicity (m b 2-5), and we accurately located $150 earthquakes. Many of the earthquakes occur at locations and depths indicative of ongoing subduction in the South Shetland trench. A focal mechanism for the largest event in the forearc indicates shallow angle thrusting. The maximum depth of seismicity is $65 km, but the majority of the events are shallower than 30 km. These seismic results are consistent with recent magnetic, GPS, and multichannel seismic reflection data that suggest continued subduction at a very slow rate. The South Shetland trench thus represents an extreme end-member of hot subduction resulting from slow convergence of young lithosphere, and the absence of intermediate depth earthquakes is consistent with thermal assimilation of the slab at shallow depths. We have located many earthquakes associated with volcanism and rifting in Bransfield Strait. A swarm of events near a submarine volcano suggests current magmatic activity. A normal faulting focal mechanism in the northeastern part of the strait gives evidence of extension. Earthquakes associated with rifting in the northeastern portion of the strait are clustered along wellestablished rifts, but the seismicity is much more diffuse to the southwest. This observation is consistent with other evidence that extension has propagated from northeast to southwest. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Stacey D Robertson Maurice Douglas A Wiens Patrick J Shore Emilio Vera Leroy M Dorman Robertson Maurice S D D A Wiens P J Shore E Vera Seismicity L M Dorman |
spellingShingle |
Stacey D Robertson Maurice Douglas A Wiens Patrick J Shore Emilio Vera Leroy M Dorman Robertson Maurice S D D A Wiens P J Shore E Vera Seismicity L M Dorman Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. |
author_facet |
Stacey D Robertson Maurice Douglas A Wiens Patrick J Shore Emilio Vera Leroy M Dorman Robertson Maurice S D D A Wiens P J Shore E Vera Seismicity L M Dorman |
author_sort |
Stacey D Robertson Maurice |
title |
Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. |
title_short |
Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. |
title_full |
Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. |
title_fullStr |
Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. |
title_full_unstemmed |
Seismicity and tectonics of the South Shetland Islands and Bransfield Strait from a regional broadband seismograph deployment. |
title_sort |
seismicity and tectonics of the south shetland islands and bransfield strait from a regional broadband seismograph deployment. |
publishDate |
2003 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1075.6667 http://epsc.wustl.edu/seismology/doug/wp-content/uploads/2013/06/robertson_jgr_2003.pdf |
long_lat |
ENVELOPE(-59.500,-59.500,-61.000,-61.000) |
geographic |
Bransfield Strait South Shetland Islands South Shetland Trench |
geographic_facet |
Bransfield Strait South Shetland Islands South Shetland Trench |
genre |
Bransfield Strait South Shetland Islands |
genre_facet |
Bransfield Strait South Shetland Islands |
op_source |
http://epsc.wustl.edu/seismology/doug/wp-content/uploads/2013/06/robertson_jgr_2003.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1075.6667 http://epsc.wustl.edu/seismology/doug/wp-content/uploads/2013/06/robertson_jgr_2003.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766380681949085696 |