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(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201203/2017Z)
(3) Volcano: Korovin (VNUM #311161)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A1279
(8) Volcano Location: N 52 deg 22 min W 174 deg 9 min
(9) Area: Aleutians
(10) Summit Elevation: 5030 ft (1533 m)
(11) Volcanic Activity Summary: Unrest at Korvin Volcano that began in late October 2020 has subsided. Seismic activity has returned to background levels and satellite observations over the past several weeks have shown no signs of unrest. Thus, AVO is decreasing the Aviation Color Code and Alert Level to GREEN/NORMAL.

Korovin is monitored by local seismic and infrasound sensors, satellite data, regional lightning detection instruments, and reports from local residents. Observations of steaming are not unusual at Korovin and meteorological conditions can enhance its visibility.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: steam from the summit crater is common
(14) Remarks: Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 21 km (13 mi) northwest of the community of Atka, 538 km (350 mi) west of Dutch Harbor, and 1760 km (1100 mi) southwest of Anchorage. The volcano has two distinct summit vents about 0.6 km (2000 ft) apart, that have been the sites of eruptive activity in historical time. The most recently active of the vents maintains a small, roiling, lake that occasionally produces energetic steam emissions. Thermal springs and fumaroles located on and near the volcano indicate an active hydrothermal system. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged from 4900 to 10,600 m (16,000 to 35,000 feet) above sea level.
(15) Contacts:
Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:

AVO/USGS Volcanic Activity Notice

Volcano: Korovin (VNUM #311161)

Current Volcano Alert Level: NORMAL
Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: GREEN
Previous Aviation Color Code: YELLOW

Issued: Thursday, December 3, 2020, 11:17 AM AKST
Source: Alaska Volcano Observatory
Notice Number: 2020/A1279
Location: N 52 deg 22 min W 174 deg 9 min
Elevation: 5030 ft (1533 m)
Area: Aleutians

Volcanic Activity Summary: Unrest at Korvin Volcano that began in late October 2020 has subsided. Seismic activity has returned to background levels and satellite observations over the past several weeks have shown no signs of unrest. Thus, AVO is decreasing the Aviation Color Code and Alert Level to GREEN/NORMAL.

Korovin is monitored by local seismic and infrasound sensors, satellite data, regional lightning detection instruments, and reports from local residents. Observations of steaming are not unusual at Korovin and meteorological conditions can enhance its visibility.


Recent Observations:
[Volcanic cloud height] n/a
[Other volcanic cloud information] steam from the summit crater is common

Hazard Analysis:
[General hazards] n/a
[Ash cloud] n/a
[Ashfall] n/a
[Lava flow/dome] n/a
[Mud flow] n/a
[Other hazards] n/a
[Volcanic gas] n/a
[Lava flow] n/a

Remarks: Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 21 km (13 mi) northwest of the community of Atka, 538 km (350 mi) west of Dutch Harbor, and 1760 km (1100 mi) southwest of Anchorage. The volcano has two distinct summit vents about 0.6 km (2000 ft) apart, that have been the sites of eruptive activity in historical time. The most recently active of the vents maintains a small, roiling, lake that occasionally produces energetic steam emissions. Thermal springs and fumaroles located on and near the volcano indicate an active hydrothermal system. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged from 4900 to 10,600 m (16,000 to 35,000 feet) above sea level.

Contacts:
Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
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.