(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20211210/2138Z)
(3) Volcano:	Davidof (VNUM #311040)
(4) Current Color Code:	YELLOW
(5) Previous Color Code:
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2021/A1108
(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:	Over the past three days a swarm of earthquakes has occurred in the vicinity of Davidof volcano. The largest earthquake to date happened this morning at about 19:45 UTC (10:45 am AKST) and had a magnitude of 4.2. This swarm may be associated with volcanic unrest or it could also be due to regional tectonic activity. Due to the possibility of escalating volcanic unrest, AVO is raising the Aviation Color Code and Volcano Alert Level for Davidof to YELLOW/ADVISORY. AVO is continuing to monitor the situation with seismometers deployed on nearby islands since there is no real-time seismic monitoring network at Davidof volcano. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island.
(12) Volcanic cloud height:	no cloud present
(13) Other volcanic cloud information:	no cloud present
(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 David Fee, Coordinating Scientist, UAF, dfee1@alaska.edu (907) 322-4085
(16) Next Notice:

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AVO/USGS Volcanic Activity Notice

Volcano: Davidof (VNUM #311040)

Current Volcano Alert Level: ADVISORY

Current Aviation Color Code: YELLOW

Issued: Friday, December 10, 2021, 12:38 PM AKST
Source: Alaska Volcano Observatory
Notice Number: 2021/A1108
Location: N 51 deg 57 min E 178 deg 19 min
Elevation: 1076 ft (328 m)
Area: Aleutians

Volcanic Activity Summary: Over the past three days a swarm of earthquakes has occurred in the vicinity of Davidof volcano. The largest earthquake to date happened this morning at about 19:45 UTC (10:45 am AKST) and had a magnitude of 4.2. This swarm may be associated with volcanic unrest or it could also be due to regional tectonic activity. Due to the possibility of escalating volcanic unrest, AVO is raising the Aviation Color Code and Volcano Alert Level for Davidof to YELLOW/ADVISORY. AVO is continuing to monitor the situation with seismometers deployed on nearby islands since there is no real-time seismic monitoring network at Davidof volcano. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island.

Recent Observations:
[Volcanic cloud height] no cloud present
[Other volcanic cloud information] no cloud present

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

David Fee, Coordinating Scientist, UAF, dfee1@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.

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