Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake
The Mw 7.9 Denali fault earthquake ruptured segments of the Susitna Glacier, Denali, and Totschunda faults in central Alaska, providing a unique opportunity to look for intermediate-term (weeks to months) responses of active volcanoes to shaking from a large earthquake. The Alaska Volcano Observator...
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ftusouthflorida:oai:digitalcommons.usf.edu:geo_facpub-1302 2023-07-30T04:03:36+02:00 Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake Sánchez, John J. McNutt, Stephen R. 2004-12-01T08:00:00Z https://digitalcommons.usf.edu/geo_facpub/303 https://doi.org/10.1785/0120040602 unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/geo_facpub/303 doi:10.1785/0120040602 https://doi.org/10.1785/0120040602 School of Geosciences Faculty and Staff Publications Earth Sciences article 2004 ftusouthflorida https://doi.org/10.1785/0120040602 2023-07-13T20:27:23Z The Mw 7.9 Denali fault earthquake ruptured segments of the Susitna Glacier, Denali, and Totschunda faults in central Alaska, providing a unique opportunity to look for intermediate-term (weeks to months) responses of active volcanoes to shaking from a large earthquake. The Alaska Volcano Observatory (avo) monitors 24 volcanoes with seismograph networks. We examined one station per volcano. Digitally-filtered data for the period four weeks before to four weeks after the mainshock were plotted at a standard scale. Mt. Wrangell, the closest volcano to the epicenter (247 km), had a background rate of 16 events/day. For the following 30 days, however, its seismicity rate dropped by 50%. Mt. Veniaminof (1400 km from the epicenter) had a rate of 8 seismic events/day, but suffered a drop in seismicity by 80% after the maishock; this may have lasted for 15 days. The seismicity at both volcanoes is dominated by long-period seismic events. With the exception of Martin and Novarupta volcanoes, the other 20 volcanoes showed no changes in seismicity attributable to the Denali fault earthquake. We conclude that the changes in seismicity observed are real, and are related to the Denali fault earthquake. These seismicity drops are in strong contrast to cases of short-term triggered seismicity increases observed at other volcanic systems such as Martin-Novarupta, Mt. Rainier, Yellowstone, Mammoth Mountain, and The Geysers, Coso and Cerro Prieto (Mexico) geothermal fields. This suggests that fundamentally different mechanisms may be acting to modify seismicity at volcanoes. Article in Journal/Newspaper glacier Alaska University of South Florida St. Petersburg: Digital USFSP Prieto ENVELOPE(-62.000,-62.000,-64.683,-64.683) Bulletin of the Seismological Society of America 94 6B S370 S383 |
institution |
Open Polar |
collection |
University of South Florida St. Petersburg: Digital USFSP |
op_collection_id |
ftusouthflorida |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Sánchez, John J. McNutt, Stephen R. Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake |
topic_facet |
Earth Sciences |
description |
The Mw 7.9 Denali fault earthquake ruptured segments of the Susitna Glacier, Denali, and Totschunda faults in central Alaska, providing a unique opportunity to look for intermediate-term (weeks to months) responses of active volcanoes to shaking from a large earthquake. The Alaska Volcano Observatory (avo) monitors 24 volcanoes with seismograph networks. We examined one station per volcano. Digitally-filtered data for the period four weeks before to four weeks after the mainshock were plotted at a standard scale. Mt. Wrangell, the closest volcano to the epicenter (247 km), had a background rate of 16 events/day. For the following 30 days, however, its seismicity rate dropped by 50%. Mt. Veniaminof (1400 km from the epicenter) had a rate of 8 seismic events/day, but suffered a drop in seismicity by 80% after the maishock; this may have lasted for 15 days. The seismicity at both volcanoes is dominated by long-period seismic events. With the exception of Martin and Novarupta volcanoes, the other 20 volcanoes showed no changes in seismicity attributable to the Denali fault earthquake. We conclude that the changes in seismicity observed are real, and are related to the Denali fault earthquake. These seismicity drops are in strong contrast to cases of short-term triggered seismicity increases observed at other volcanic systems such as Martin-Novarupta, Mt. Rainier, Yellowstone, Mammoth Mountain, and The Geysers, Coso and Cerro Prieto (Mexico) geothermal fields. This suggests that fundamentally different mechanisms may be acting to modify seismicity at volcanoes. |
format |
Article in Journal/Newspaper |
author |
Sánchez, John J. McNutt, Stephen R. |
author_facet |
Sánchez, John J. McNutt, Stephen R. |
author_sort |
Sánchez, John J. |
title |
Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake |
title_short |
Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake |
title_full |
Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake |
title_fullStr |
Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake |
title_full_unstemmed |
Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002, Mw 7.9 Denali Fault Earthquake |
title_sort |
intermediate-term declines in seismicity at mt. wrangell and mt. veniaminof volcanoes, alaska, following the november 3, 2002, mw 7.9 denali fault earthquake |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2004 |
url |
https://digitalcommons.usf.edu/geo_facpub/303 https://doi.org/10.1785/0120040602 |
long_lat |
ENVELOPE(-62.000,-62.000,-64.683,-64.683) |
geographic |
Prieto |
geographic_facet |
Prieto |
genre |
glacier Alaska |
genre_facet |
glacier Alaska |
op_source |
School of Geosciences Faculty and Staff Publications |
op_relation |
https://digitalcommons.usf.edu/geo_facpub/303 doi:10.1785/0120040602 https://doi.org/10.1785/0120040602 |
op_doi |
https://doi.org/10.1785/0120040602 |
container_title |
Bulletin of the Seismological Society of America |
container_volume |
94 |
container_issue |
6B |
container_start_page |
S370 |
op_container_end_page |
S383 |
_version_ |
1772814626383200256 |