Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction
Centroid moment tensor solutions are recomputed for 190 earthquakes from 1976 to 2010 along the Heezen, Tharp and Hollister transform faults of the Eltanin system using a 3-D seismic velocity model. The total length of the three en echelon faults is nearly 1000 km; each is characterized by fast long...
Published in: | Geophysical Journal International |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2012
|
Subjects: | |
Online Access: | https://gfzpublic.gfz-potsdam.de/pubman/item/item_3084914 |
id |
ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_3084914 |
---|---|
record_format |
openpolar |
spelling |
ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_3084914 2023-05-15T13:35:24+02:00 Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction Sykes, L. Ekström, G. 2012 https://gfzpublic.gfz-potsdam.de/pubman/item/item_3084914 eng eng info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-246X.2011.05284.x https://gfzpublic.gfz-potsdam.de/pubman/item/item_3084914 Geophysical Journal International info:eu-repo/semantics/article 2012 ftgfzpotsdam https://doi.org/10.1111/j.1365-246X.2011.05284.x 2022-09-14T05:56:18Z Centroid moment tensor solutions are recomputed for 190 earthquakes from 1976 to 2010 along the Heezen, Tharp and Hollister transform faults of the Eltanin system using a 3-D seismic velocity model. The total length of the three en echelon faults is nearly 1000 km; each is characterized by fast long-term rates of displacement of about 80 mm yr-1. Strike-slip faulting with moment magnitudes Mw up to 6.4 characterizes most of these events. The few involving normal faulting are located up to 40 km on either side of the transforms and involve extension nearly normal to the transforms. This partitioning of slip likely results from changes during the last few million years in the Euler pole for relative motion between the Antarctic and Pacific plates. Some parts of the Heezen and Tharp transforms exhibit strong seismic coupling but others were aseismic at the resolution of our study, Mw > 5.0-5.5. Earthquakes were not found along nearby fast spreading ridges at that resolution. We calculate downdip widths of seismic coupling of about 5 km for four strongly coupled segments from observed moment rates and lengths along strike assuming earthquake activity accounts for the entire plate motion. Major differences in seismic coupling along strike are not in accord with common thermal models of plate cooling but instead are attributed to varying degrees of metamorphism, rock type and effective normal stress and possibly to the presence of short intratransform spreading centres. One 30-42-km-long segment of the Heezen transform that appears to be an isolated well-coupled asperity has ruptured in eight earthquakes of Mw 5.9-6.1 quasi-periodically with a coefficient of variation of 0.26 every 4.0 ± 1.0 yr. Other well-coupled fault segments, which were sites with earthquakes up to Mw 6.39 and fewer events since 1976, have average repeat times of about 7-24 yr. The fast rate of plate motion, maximum size of events and relatively short repeat times make these fault segments a good laboratory for research on quasi-periodic ... Article in Journal/Newspaper Antarc* Antarctic GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic The Antarctic Pacific Geophysical Journal International 188 2 421 434 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
Centroid moment tensor solutions are recomputed for 190 earthquakes from 1976 to 2010 along the Heezen, Tharp and Hollister transform faults of the Eltanin system using a 3-D seismic velocity model. The total length of the three en echelon faults is nearly 1000 km; each is characterized by fast long-term rates of displacement of about 80 mm yr-1. Strike-slip faulting with moment magnitudes Mw up to 6.4 characterizes most of these events. The few involving normal faulting are located up to 40 km on either side of the transforms and involve extension nearly normal to the transforms. This partitioning of slip likely results from changes during the last few million years in the Euler pole for relative motion between the Antarctic and Pacific plates. Some parts of the Heezen and Tharp transforms exhibit strong seismic coupling but others were aseismic at the resolution of our study, Mw > 5.0-5.5. Earthquakes were not found along nearby fast spreading ridges at that resolution. We calculate downdip widths of seismic coupling of about 5 km for four strongly coupled segments from observed moment rates and lengths along strike assuming earthquake activity accounts for the entire plate motion. Major differences in seismic coupling along strike are not in accord with common thermal models of plate cooling but instead are attributed to varying degrees of metamorphism, rock type and effective normal stress and possibly to the presence of short intratransform spreading centres. One 30-42-km-long segment of the Heezen transform that appears to be an isolated well-coupled asperity has ruptured in eight earthquakes of Mw 5.9-6.1 quasi-periodically with a coefficient of variation of 0.26 every 4.0 ± 1.0 yr. Other well-coupled fault segments, which were sites with earthquakes up to Mw 6.39 and fewer events since 1976, have average repeat times of about 7-24 yr. The fast rate of plate motion, maximum size of events and relatively short repeat times make these fault segments a good laboratory for research on quasi-periodic ... |
format |
Article in Journal/Newspaper |
author |
Sykes, L. Ekström, G. |
spellingShingle |
Sykes, L. Ekström, G. Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
author_facet |
Sykes, L. Ekström, G. |
author_sort |
Sykes, L. |
title |
Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
title_short |
Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
title_full |
Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
title_fullStr |
Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
title_full_unstemmed |
Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
title_sort |
earthquakes along eltanin transform system, se pacific ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction |
publishDate |
2012 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_3084914 |
geographic |
Antarctic The Antarctic Pacific |
geographic_facet |
Antarctic The Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Geophysical Journal International |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-246X.2011.05284.x https://gfzpublic.gfz-potsdam.de/pubman/item/item_3084914 |
op_doi |
https://doi.org/10.1111/j.1365-246X.2011.05284.x |
container_title |
Geophysical Journal International |
container_volume |
188 |
container_issue |
2 |
container_start_page |
421 |
op_container_end_page |
434 |
_version_ |
1766065265180672000 |