Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska
Abstract Tanaga Island in the Central Aleutian Islands includes four stratovolcanoes: Sajaka, Tanaga, and East Tanaga in the northwest, and Takawangha in the central part of the island. Of these volcanoes, only Tanaga has a confirmed record of historical eruptive activity. We use double‐difference m...
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| Format: | Article |
| Language: | English |
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Wiley
2023-06-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2023GC010891 |
| _version_ | 1797638083792863232 |
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| author | Kevin F. Lally Jacqueline Caplan‐Auerbach John A. Power |
| author_facet | Kevin F. Lally Jacqueline Caplan‐Auerbach John A. Power |
| author_sort | Kevin F. Lally |
| collection | DOAJ |
| description | Abstract Tanaga Island in the Central Aleutian Islands includes four stratovolcanoes: Sajaka, Tanaga, and East Tanaga in the northwest, and Takawangha in the central part of the island. Of these volcanoes, only Tanaga has a confirmed record of historical eruptive activity. We use double‐difference methods to relocate Tanaga Island earthquakes from the period 2003–2017 to gain insight into volcanic and tectonic activity in the region. High precision relative relocations show subsurface structures in the Tanaga region related to volcanism and crustal tectonics. In 2005, a swarm of ∼600 volcano‐tectonic events located below the NW portion of the island culminated with an episode of volcanic tremor. Although there was no known eruption associated with this swarm, we suggest that this activity is associated with fluids beneath Takawangha volcano. Overall, relatively little seismicity appears to be associated with volcanism: of 5,680 earthquakes relocated in this study, only ∼700 took place within 10 km of the volcanoes themselves. Other regions appear to experience primarily, if not exclusively, tectonic seismicity. Two regions on Tanaga Island became seismically active following a M6.6 tectonic earthquake east of the island on 2 May 2008, suggesting the triggering of tectonic earthquakes by the M6.6. Seismic activity recorded offshore and below the southern part of the island is interpreted as due to the clockwise rotation of the Delarof Block in the forearc, and bookshelf faulting along the volcanic arc. This suggests a complex pattern of earthquake hypocenters governed by both volcanic and tectonic processes surrounding Tanaga and Takawangha volcanoes. |
| first_indexed | 2024-03-11T12:57:33Z |
| format | Article |
| id | doaj.art-72214495fb324255a474bfac60793411 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:57:33Z |
| publishDate | 2023-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-72214495fb324255a474bfac607934112023-11-03T16:56:13ZengWileyGeochemistry, Geophysics, Geosystems1525-20272023-06-01246n/an/a10.1029/2023GC010891Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, AlaskaKevin F. Lally0Jacqueline Caplan‐Auerbach1John A. Power2Geology Department Western Washington University Bellingham WA USAGeology Department Western Washington University Bellingham WA USAU.S. Geological Survey Alaska Volcano Observatory Anchorage AK USAAbstract Tanaga Island in the Central Aleutian Islands includes four stratovolcanoes: Sajaka, Tanaga, and East Tanaga in the northwest, and Takawangha in the central part of the island. Of these volcanoes, only Tanaga has a confirmed record of historical eruptive activity. We use double‐difference methods to relocate Tanaga Island earthquakes from the period 2003–2017 to gain insight into volcanic and tectonic activity in the region. High precision relative relocations show subsurface structures in the Tanaga region related to volcanism and crustal tectonics. In 2005, a swarm of ∼600 volcano‐tectonic events located below the NW portion of the island culminated with an episode of volcanic tremor. Although there was no known eruption associated with this swarm, we suggest that this activity is associated with fluids beneath Takawangha volcano. Overall, relatively little seismicity appears to be associated with volcanism: of 5,680 earthquakes relocated in this study, only ∼700 took place within 10 km of the volcanoes themselves. Other regions appear to experience primarily, if not exclusively, tectonic seismicity. Two regions on Tanaga Island became seismically active following a M6.6 tectonic earthquake east of the island on 2 May 2008, suggesting the triggering of tectonic earthquakes by the M6.6. Seismic activity recorded offshore and below the southern part of the island is interpreted as due to the clockwise rotation of the Delarof Block in the forearc, and bookshelf faulting along the volcanic arc. This suggests a complex pattern of earthquake hypocenters governed by both volcanic and tectonic processes surrounding Tanaga and Takawangha volcanoes.https://doi.org/10.1029/2023GC010891volcano monitoringsubduction zone processesvolcano seismologyseismicity and tectonics |
| spellingShingle | Kevin F. Lally Jacqueline Caplan‐Auerbach John A. Power Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska Geochemistry, Geophysics, Geosystems volcano monitoring subduction zone processes volcano seismology seismicity and tectonics |
| title | Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska |
| title_full | Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska |
| title_fullStr | Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska |
| title_full_unstemmed | Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska |
| title_short | Volcanic and Tectonic Sources of Seismicity Near the Tanaga Volcanic Cluster, Alaska |
| title_sort | volcanic and tectonic sources of seismicity near the tanaga volcanic cluster alaska |
| topic | volcano monitoring subduction zone processes volcano seismology seismicity and tectonics |
| url | https://doi.org/10.1029/2023GC010891 |
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