Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E
The ultraslow spreading Southwest Indian Ridge (SWIR) is a prominent end member of the global mid-ocean ridge system. It spreads with a full-rate of 14 mm/y to 16 mm/y and shows several segments of various obliquities. The western SWIR consists of the Oblique and Orthogonal Supersegments lying at an...
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Online Access: | https://epic.awi.de/id/eprint/26039/ http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.2012.05480.x/abstract https://hdl.handle.net/10013/epic.39379 |
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ftawi:oai:epic.awi.de:26039 2024-09-15T17:42:06+00:00 Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E Läderach, Christine Korger, Edith Schlindwein, Vera Müller, Christian Eckstaller, Alfons 2012-05-11 https://epic.awi.de/id/eprint/26039/ http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.2012.05480.x/abstract https://hdl.handle.net/10013/epic.39379 unknown WILEY-BLACKWELL PUBLISHING Läderach, C. , Korger, E. , Schlindwein, V. orcid:0000-0001-5570-2753 , Müller, C. and Eckstaller, A. (2012) Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E , Geophysical Journal International . doi:10.1111/j.1365-246X.2012.05480.x <https://doi.org/10.1111/j.1365-246X.2012.05480.x> , hdl:10013/epic.39379 EPIC3Geophysical Journal International, WILEY-BLACKWELL PUBLISHING, ISSN: 0956-540X Article isiRev 2012 ftawi https://doi.org/10.1111/j.1365-246X.2012.05480.x 2024-06-24T04:03:41Z The ultraslow spreading Southwest Indian Ridge (SWIR) is a prominent end member of the global mid-ocean ridge system. It spreads with a full-rate of 14 mm/y to 16 mm/y and shows several segments of various obliquities. The western SWIR consists of the Oblique and Orthogonal Supersegments lying at an epicentral distance of ~21° to the VNA2 seismic array operated by the German Neumayer station in East Antarctica. The array monitors backazimuth, apparent velocity and signal-to-noise ratio of arriving waves and provides a dataset of seismicity from the western SWIR over several years. Compared to the global seismological network, its detection threshold for earthquakes occurring at the western SWIR is more than 0.5 mb lower enabling a more comprehensive study of mid-ocean ridge processes than the teleseismic earthquake catalogues. We identified a total number of 743 earthquakes occurring at the western part of the SWIR and calculated the body-wave magnitudes (mb) from P-wave amplitude picks on the VNA2 broadband sensor obtaining a magnitude range from mb 3.18 to mb 5.34. In the years of 2001, 2004, 2005 and 2008, significantly increased event rates indicated four earthquake swarms with up to 164 events lasting for several days. All swarms had strong events registered in the International Seismological Centre (ISC) catalogue. The relocalization of these events confirmed that all swarms occurred in the same region on the Orthogonal Supersegment. We analysed event and moment release rate histories, b-values and aftershock decay rates (Modified Omori Law) finding that the swarms of 2001, 2004 and 2005 have similarities in the temporal distribution of seismic moment and event numbers. The swarm of 2008 is smaller with high magnitude events at the swarm’s onset which represent shear failure on normal faults. The application of the Modified Omori Law and the b-value show that the earthquakes of the swarms do not follow the classical mainshock-aftershock pattern of purely tectonic earthquake sequences. At the Orthogonal ... Article in Journal/Newspaper Antarc* Antarctica East Antarctica Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Geophysical Journal International 190 1 429 441 |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
unknown |
description |
The ultraslow spreading Southwest Indian Ridge (SWIR) is a prominent end member of the global mid-ocean ridge system. It spreads with a full-rate of 14 mm/y to 16 mm/y and shows several segments of various obliquities. The western SWIR consists of the Oblique and Orthogonal Supersegments lying at an epicentral distance of ~21° to the VNA2 seismic array operated by the German Neumayer station in East Antarctica. The array monitors backazimuth, apparent velocity and signal-to-noise ratio of arriving waves and provides a dataset of seismicity from the western SWIR over several years. Compared to the global seismological network, its detection threshold for earthquakes occurring at the western SWIR is more than 0.5 mb lower enabling a more comprehensive study of mid-ocean ridge processes than the teleseismic earthquake catalogues. We identified a total number of 743 earthquakes occurring at the western part of the SWIR and calculated the body-wave magnitudes (mb) from P-wave amplitude picks on the VNA2 broadband sensor obtaining a magnitude range from mb 3.18 to mb 5.34. In the years of 2001, 2004, 2005 and 2008, significantly increased event rates indicated four earthquake swarms with up to 164 events lasting for several days. All swarms had strong events registered in the International Seismological Centre (ISC) catalogue. The relocalization of these events confirmed that all swarms occurred in the same region on the Orthogonal Supersegment. We analysed event and moment release rate histories, b-values and aftershock decay rates (Modified Omori Law) finding that the swarms of 2001, 2004 and 2005 have similarities in the temporal distribution of seismic moment and event numbers. The swarm of 2008 is smaller with high magnitude events at the swarm’s onset which represent shear failure on normal faults. The application of the Modified Omori Law and the b-value show that the earthquakes of the swarms do not follow the classical mainshock-aftershock pattern of purely tectonic earthquake sequences. At the Orthogonal ... |
format |
Article in Journal/Newspaper |
author |
Läderach, Christine Korger, Edith Schlindwein, Vera Müller, Christian Eckstaller, Alfons |
spellingShingle |
Läderach, Christine Korger, Edith Schlindwein, Vera Müller, Christian Eckstaller, Alfons Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E |
author_facet |
Läderach, Christine Korger, Edith Schlindwein, Vera Müller, Christian Eckstaller, Alfons |
author_sort |
Läderach, Christine |
title |
Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E |
title_short |
Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E |
title_full |
Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E |
title_fullStr |
Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E |
title_full_unstemmed |
Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E |
title_sort |
characteristics of tectono-magmatic earthquake swarms at the southwest indian ridge between 16°e and 25°e |
publisher |
WILEY-BLACKWELL PUBLISHING |
publishDate |
2012 |
url |
https://epic.awi.de/id/eprint/26039/ http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.2012.05480.x/abstract https://hdl.handle.net/10013/epic.39379 |
genre |
Antarc* Antarctica East Antarctica |
genre_facet |
Antarc* Antarctica East Antarctica |
op_source |
EPIC3Geophysical Journal International, WILEY-BLACKWELL PUBLISHING, ISSN: 0956-540X |
op_relation |
Läderach, C. , Korger, E. , Schlindwein, V. orcid:0000-0001-5570-2753 , Müller, C. and Eckstaller, A. (2012) Characteristics of tectono-magmatic earthquake swarms at the Southwest Indian Ridge between 16°E and 25°E , Geophysical Journal International . doi:10.1111/j.1365-246X.2012.05480.x <https://doi.org/10.1111/j.1365-246X.2012.05480.x> , hdl:10013/epic.39379 |
op_doi |
https://doi.org/10.1111/j.1365-246X.2012.05480.x |
container_title |
Geophysical Journal International |
container_volume |
190 |
container_issue |
1 |
container_start_page |
429 |
op_container_end_page |
441 |
_version_ |
1810488530868109312 |