Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska
[1] High-resolution sparker and crustal-scale air gun seismic reflection data, coupled with repeat bathymetric surveys, document a region of repeated coseismic uplift on the portion of the Alaska subduction zone that ruptured in 1964. This area defines the western limit of Prince William Sound. Diff...
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ftboisestateu:oai:scholarworks.boisestate.edu:cgiss_facpubs-1189 2023-10-29T02:40:46+01:00 Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska Liberty, Lee M. Finn, Shaun P. Haeussler, Peter J. Pratt, Thomas L. Peterson, Andrew 2013-10-01T07:00:00Z application/pdf https://scholarworks.boisestate.edu/cgiss_facpubs/190 https://scholarworks.boisestate.edu/context/cgiss_facpubs/article/1189/viewcontent/Liberty___Megathrust_splay_faults.pdf unknown ScholarWorks https://scholarworks.boisestate.edu/cgiss_facpubs/190 https://scholarworks.boisestate.edu/context/cgiss_facpubs/article/1189/viewcontent/Liberty___Megathrust_splay_faults.pdf Copyright 2013 by the American Geophysical Union. DOI: 10.1002/jgrb.50372 CGISS Publications and Presentations megathrust splay fault Alaska subduction Geosciences Earth Sciences Geophysics and Seismology text 2013 ftboisestateu 2023-09-29T15:03:46Z [1] High-resolution sparker and crustal-scale air gun seismic reflection data, coupled with repeat bathymetric surveys, document a region of repeated coseismic uplift on the portion of the Alaska subduction zone that ruptured in 1964. This area defines the western limit of Prince William Sound. Differencing of vintage and modern bathymetric surveys shows that the region of greatest uplift related to the 1964 Great Alaska earthquake was focused along a series of subparallel faults beneath Prince William Sound and the adjacent Gulf of Alaska shelf. Bathymetric differencing indicates that 12 m of coseismic uplift occurred along two faults that reached the seafloor as submarine terraces on the Cape Cleare bank southwest of Montague Island. Sparker seismic reflection data provide cumulative Holocene slip estimates as high as 9 mm/yr along a series of splay thrust faults within both the inner wedge and transition zone of the accretionary prism. Crustal seismic data show that these megathrust splay faults root separately into the subduction zone décollement. Splay fault divergence from this megathrust correlates with changes in midcrustal seismic velocity and magnetic susceptibility values, best explained by duplexing of the subducted Yakutat terrane rocks above Pacific plate rocks along the trailing edge of the Yakutat terrane. Although each splay fault is capable of independent motion, we conclude that the identified splay faults rupture in a similar pattern during successive megathrust earthquakes and that the region of greatest seismic coupling has remained consistent throughout the Holocene. Text Yakutat Alaska Boise State University: Scholar Works |
institution |
Open Polar |
collection |
Boise State University: Scholar Works |
op_collection_id |
ftboisestateu |
language |
unknown |
topic |
megathrust splay fault Alaska subduction Geosciences Earth Sciences Geophysics and Seismology |
spellingShingle |
megathrust splay fault Alaska subduction Geosciences Earth Sciences Geophysics and Seismology Liberty, Lee M. Finn, Shaun P. Haeussler, Peter J. Pratt, Thomas L. Peterson, Andrew Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska |
topic_facet |
megathrust splay fault Alaska subduction Geosciences Earth Sciences Geophysics and Seismology |
description |
[1] High-resolution sparker and crustal-scale air gun seismic reflection data, coupled with repeat bathymetric surveys, document a region of repeated coseismic uplift on the portion of the Alaska subduction zone that ruptured in 1964. This area defines the western limit of Prince William Sound. Differencing of vintage and modern bathymetric surveys shows that the region of greatest uplift related to the 1964 Great Alaska earthquake was focused along a series of subparallel faults beneath Prince William Sound and the adjacent Gulf of Alaska shelf. Bathymetric differencing indicates that 12 m of coseismic uplift occurred along two faults that reached the seafloor as submarine terraces on the Cape Cleare bank southwest of Montague Island. Sparker seismic reflection data provide cumulative Holocene slip estimates as high as 9 mm/yr along a series of splay thrust faults within both the inner wedge and transition zone of the accretionary prism. Crustal seismic data show that these megathrust splay faults root separately into the subduction zone décollement. Splay fault divergence from this megathrust correlates with changes in midcrustal seismic velocity and magnetic susceptibility values, best explained by duplexing of the subducted Yakutat terrane rocks above Pacific plate rocks along the trailing edge of the Yakutat terrane. Although each splay fault is capable of independent motion, we conclude that the identified splay faults rupture in a similar pattern during successive megathrust earthquakes and that the region of greatest seismic coupling has remained consistent throughout the Holocene. |
format |
Text |
author |
Liberty, Lee M. Finn, Shaun P. Haeussler, Peter J. Pratt, Thomas L. Peterson, Andrew |
author_facet |
Liberty, Lee M. Finn, Shaun P. Haeussler, Peter J. Pratt, Thomas L. Peterson, Andrew |
author_sort |
Liberty, Lee M. |
title |
Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska |
title_short |
Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska |
title_full |
Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska |
title_fullStr |
Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska |
title_full_unstemmed |
Megathrust Splay Faults at the Focus of the Prince William Sound Asperity, Alaska |
title_sort |
megathrust splay faults at the focus of the prince william sound asperity, alaska |
publisher |
ScholarWorks |
publishDate |
2013 |
url |
https://scholarworks.boisestate.edu/cgiss_facpubs/190 https://scholarworks.boisestate.edu/context/cgiss_facpubs/article/1189/viewcontent/Liberty___Megathrust_splay_faults.pdf |
genre |
Yakutat Alaska |
genre_facet |
Yakutat Alaska |
op_source |
CGISS Publications and Presentations |
op_relation |
https://scholarworks.boisestate.edu/cgiss_facpubs/190 https://scholarworks.boisestate.edu/context/cgiss_facpubs/article/1189/viewcontent/Liberty___Megathrust_splay_faults.pdf |
op_rights |
Copyright 2013 by the American Geophysical Union. DOI: 10.1002/jgrb.50372 |
_version_ |
1781069500936880128 |