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USGS Volcano Notice - DOI-USGS-AVO-2021-12-29T11:34:06-09:00
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AVO/USGS Volcanic Activity Notice
Volcano: Davidof (VNUM #311040)
Current Volcano Alert Level: UNASSIGNED
Previous Volcano Alert Level: ADVISORY
Current Aviation Color Code: UNASSIGNED
Previous Aviation Color Code: YELLOW
Issued: Wednesday, December 29, 2021, 12:11 PM AKST
Source: Alaska Volcano Observatory
Notice Number: 2021/A1184
Location: N 51 deg 57 min E 178 deg 19 min
Elevation: 1076 ft (328 m)
Area: Aleutians
Volcanic Activity Summary: The swarm of earthquakes that occurred in the vicinity of Davidof volcano beginning in early December has subsided. Thus, the Aviation Color Code and Alert Level is being decreased to UNASSIGNED/UNASSIGNED. AVO only assigns color code and alert level values to volcanoes that are sufficiently instrumented to allow us to understand the background state of activity. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island, and are insufficient to allow us to assign specific alert levels. Thus, UNASSIGNED is used.
Recent Observations:
[Volcanic cloud height] n/a
[Other volcanic cloud information] Unknown
Remarks: Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof.
Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497
Pavel Izbekov, Acting Coordinating Scientist, UAFGI, peizbekov@alaska.edu (907) 322-4085
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
Volcano: Davidof (VNUM #311040)
Current Volcano Alert Level: UNASSIGNED
Previous Volcano Alert Level: ADVISORY
Current Aviation Color Code: UNASSIGNED
Previous Aviation Color Code: YELLOW
Issued: Wednesday, December 29, 2021, 12:11 PM AKST
Source: Alaska Volcano Observatory
Notice Number: 2021/A1184
Location: N 51 deg 57 min E 178 deg 19 min
Elevation: 1076 ft (328 m)
Area: Aleutians
Volcanic Activity Summary: The swarm of earthquakes that occurred in the vicinity of Davidof volcano beginning in early December has subsided. Thus, the Aviation Color Code and Alert Level is being decreased to UNASSIGNED/UNASSIGNED. AVO only assigns color code and alert level values to volcanoes that are sufficiently instrumented to allow us to understand the background state of activity. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island, and are insufficient to allow us to assign specific alert levels. Thus, UNASSIGNED is used.
Recent Observations:
[Volcanic cloud height] n/a
[Other volcanic cloud information] Unknown
Remarks: Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof.
Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497
Pavel Izbekov, Acting Coordinating Scientist, UAFGI, peizbekov@alaska.edu (907) 322-4085
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20211229/2111Z) |
| (3) Volcano: | Davidof (VNUM #311040) |
| (4) Current Color Code: | UNASSIGNED |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2021/A1184 |
| (8) Volcano Location: | N 51 deg 57 min E 178 deg 19 min |
| (9) Area: | Aleutians |
| (10) Summit Elevation: | 1076 ft (328 m) |
| (11) Volcanic Activity Summary: | The swarm of earthquakes that occurred in the vicinity of Davidof volcano beginning in early December has subsided. Thus, the Aviation Color Code and Alert Level is being decreased to UNASSIGNED/UNASSIGNED. AVO only assigns color code and alert level values to volcanoes that are sufficiently instrumented to allow us to understand the background state of activity. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island, and are insufficient to allow us to assign specific alert levels. Thus, UNASSIGNED is used. |
| (12) Volcanic cloud height: | n/a |
| (13) Other volcanic cloud information: | Unknown |
| (14) Remarks: | Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497 Pavel Izbekov, Acting Coordinating Scientist, UAFGI, peizbekov@alaska.edu (907) 322-4085 |
| (16) Next Notice: | |