AVO can no longer seismically monitor the following volcanoes because of seismic station outages. As a result, AVO is unable to (1) assess whether these volcanoes may be building towards an eruption and (2) quickly confirm or dismiss reports of activity at these volcanoes.
Veniaminof
Aniakchak
Fourpeaked
Korovin
Because these volcanoes are no longer seismically monitored, they will move from volcano alert level Normal and aviation color code Green to "unassigned". They will likely remain without real-time seismic monitoring until next summer, when necessary upgrades at these and other networks will occur. As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data and reports from pilots and ground observers to detect signs of eruptive activity. Complete report text
Current located earthquake counts at Korovin volcano, updated daily, Monday through Friday. The red line gives a running count, with the total count being where the line hits the y-axis on the right side of the image. Click for larger image.
Korovin portion of weekly Updates and periodic Information Releases.
Earlier today, AVO lowered the Aviation Color Code to GREEN, and the Volcanic Activity Alert Level to Normal at Korovin. Over the last several months, seismicity rates have declined to near background levels. Recent satellite data also indicate that ground deformation at Korovin has slowed markedly, perhaps ceasing altogether, after a period of uplift from approximately mid-summer 2006 through early-spring 2007.
AVO is lowering the Aviation Color Code to GREEN, and the Volcanic Activity Alert Level to Normal at Korovin. The volcano has been at Color Code YELLOW and Alert Level Advisory since November 6, 2006. Over the last several months, seismicity rates have declined to near background levels. Recent satellite data also indicate that ground deformation at Korovin has slowed markedly, and perhaps ceased altogether, after a period of uplift from approximately mid-summer 2006 through early-spring 2007.
Steam emissions from Korovin and occasional bursts of low-level earthquakes or volcanic tremor will likely still occur, but both of these phenomena are typical of background activity for this volcano, which has a long-lived, well-developed hydrothermal system.
An earthquake swarm, consisting of about 40 located events with a maximum magnitude of 1.2, occurred on August 19-20 about 5 km southeast of Korovin. Cloudy conditions prevented views of the volcano by satellite for most of the past week.
Intermittent, low-level seismic activity continues at Korovin. Cloudy conditions prevented views of the volcano by satellite for most of the past week.
Intermittent, low-level seismic activity continues at Korovin. Cloudy conditions prevented views of the volcano by satellite for most of the past week.
Intermittent, low-level seismic activity continues at Korovin throughout the week. On Monday, residents in Atka reported a robust steam plume rising 700-800 ft (200-250 m) above the volcano. These have been noted before and do not indicate a signficant change at the volcano. Clouds obscured the volcano for much of the week preventing clear satellite views.
Intermittent, low-level seismic activity continues at Korovin. Clouds obscured the volcano in satellite views most of the week. AVO has received no new information about activity at Korovin this past week.
Intermittent, low-level seismic activity continues at Korovin. Clouds obscured the volcano in satellite views most of the week. AVO has received no new information about activity at Korovin this past week.
Intermittent, low-level seismic activity continues at Korovin volcano. Low-level volcanic tremor was occasionally observed this week. Satellite views of the volcano have been obscured by clouds throughout the week.
Intermittent, low-level seismic activity continues at Korovin volcano. Low-level volcanic tremor was occasionally observed throughout the week. Clouds obscured the volcano in satellite data this week.
Intermittent, low-level seismic activity continues at Korovin. Clouds obscured the view of the volcano in satellite images throughout most of the week.
Low-level seismic activity continues at Korovin. Clouds obscured views of the volcano by satellite all week. AVO has received no reports of unusual activity from Atka.
Low-level seismic activity continues at Korovin. Clouds obscured views of the volcano by satellite all week. AVO has received no reports of unusual activity from Atka.
Low-level seismic activity continues at Korovin. Brief intervals of volcanic tremor occurred this week, but it is not known if these correspond to discrete steam plumes or eruptive activity at the volcano. Clouds obscured views of the volcano by satellite all week.
Low-level seismic activity continues at Korovin. Seismic data flow has been intermittent this past week, and we are making attempts to fix the problem. Clouds obscured views of the volcano by satellite all week.
Slightly elevated seismicity continues at Korovin. Clouds obscured views of the volcano by satellite much of the past week. No unusual activity was observed in intermittent clear views and AVO has received no new information about activity.
Slightly elevated seismicity continues at Korovin. The volcano was obscured by clouds in satellite images over the past week and AVO has received no new information about activity.
Elevated seismicity continues at Korovin Volcano. Clouds obscured views of the volcano by satellite most of the week. AVO received photographs of Korovin taken from Atka Village that show a very light dusting of ash on the upper west flank of the volcano on Saturday, March 3. Minor, low-level ash emissions are not unusual and may continue based on the level of seismic unrest detected at the volcano. Since March 3, AVO has received no additional information concerning unrest at Korovin.
Elevated seismicity continues at Korovin Volcano. Clouds obscured views of the volcano by satellite all week. AVO did not receive any additional information concerning unrest at Korovin this week.
Seismic activity at Korovin volcano continues and remains above background. A steam plume rising to more than 5000 feet above sea level was report by a pilot on Wednesday. Clear satellite observations showed no indications of other activity this week.
Seismic activity at Korovin volcano continues and remains above background. Partly cloudy satellite observations showed no indications of activity this week.
Seismic activity at Korovin volcano continues and remains above background. Cloudy conditions have obscured views of the volcano by satellite this past week.
Seismic activity at Korovin volcano continues and remains above background. Early in the week, a short-lived increase in activity appeared to conicide with Atka resident reports of increased steam emission from the volcano. Since then, cloudy conditions have prevented further observations. Increased steaming has been observed in the past and may not necessarily indicate a significant change at the volcano.
Seismic activity at Korovin volcano continues and remains above background. Extensive cloud cover in the region during the week has prevented examination of the volcano in satellite images. AVO has received no new information this week about activity at Korovin.
Seismicity near Korovin remains above background. A brief period of elevated earthquake activity was observed Thursday and has since decreased to previous levels. Cloudy conditions have obscured views of the volcano by satellite and web camera this past week. AVO has received no new information about activity at Korovin.
Seismicity near Korovin remains above background. Nothing out of the ordinary was detected this week in satellite views. We have had no new reports of steaming from Korovin since December 24.
Seismicity near Korovin remains above background. On December 24, a resident of Atka village reported and photographed a steam plume rising from Korovin. The steam plume appeared similar to those observed earlier this month and in October, 2006. Although these plumes are primarily steam, they may include minor amounts of volcanic ash. However, ash from these events is not likely to extend beyond the upper flanks of Korovin.
Northern Atka Island is home to at least two potentially active volcanic vents. While Korovin is the source of recent steam emission, the current seismicity is located under neighboring Mount Kliuchef. Because seismicity does not always indicate the potential eruptive source vent, AVO will continue to refer to Korovin Volcano unless new data allow us to be more specific.
Elevated seismic activity continued this week at Korovin. Cloudy conditions obscured the volcano in satellite images for most of the week. On Thursday, an Atka resident reported a steam plume from Korovin, possibly containing light ash.
Elevated seismic activity continued this week at Korovin. Cloudy conditions obscured the volcano in satellite images for most of the week. A break in weather on Monday allowed Atka residents to see and photograph a steam plume from the volcano.
Seismicity at Korovin remains above background. Satellite information obtained earlier in the week showed a very light dusting of ash on the eastern flank of Korovin’s main crater. Several small plumes and/or their shadows were also visible along the north side of the crater. During other times this week, clouds obscured views of the volcano by satellite. Preliminary data obtained from radar satellite images indicate that deformation of the volcano has occurred and this could be caused by the injection of new magma. The area of uplift is consistent with locations of earthquake swarms. It is uncertain if the amount of deformation observed indicates a greater or lesser probability of a future eruption.
Seismicity at Korovin remains above background. Clouds obscured views of the volcano by satellite this week and AVO received no new information about activity at Korovin.
On Monday, November 6, AVO raised the Aviation Color Code to Yellow, and the Volcanic Activity Alert Level to Advisory at Korovin Volcano on northern Atka Island. This was based on elevated seismicity, observed since July 2006, episodes of volcanic tremor, seen since September and gradually increasing in number, and steam emissions from Korovin, observed from the village of Atka on October 28.
Over the past week, seismic levels continued to be above background. No volcanic activity was observed in satellite data this week.
Northern Atka Island is home to at least two potentially active volcanic vents. While Korovin Volcano is the source of recent steam emission, and known to be active historically, the current seismicity is located under neighboring Mount Kliuchef. Because seismicity does not always indicate the potential eruptive source vent, AVO will continue to refer to Korovin Volcano in its updates and information releases, unless new data allow us to be more specific.
The number of located earthquakes at Korovin Volcano began to increase in July 2006 and has remained at elevated levels since then. Episodes of volcanic tremor have occurred in September and October, and have increased in number, strength and duration over the past several weeks. Steam emissions to several hundred meters above the volcano were observed and photographed by residents of Atka on October 28. The combination of earthquake activity, tremor episodes, and steam emissions are higher than normal background. Thus, AVO is raising the Aviation Color Code to Yellow, and the Volcanic Activity Alert Level to Advisory at Korovin.
2009-11-17 11:32:26 - VAN/VONA
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