AVO Weekly Update for 9/7/07

Current AVO Weekly Update:

Friday, September 7, 2007 4:40 PM AKDT (040 UTC)

PAVLOF VOLCANO (CAVW#1102-03-)
55°24′57″ N161°53′24″ W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

The eruption of Pavlof Volcano that began August 15th continues. Seismicity this week has slightly declined from levels recorded last week but is still characterized by volcanic tremor, frequent explosions, and debris flow signals. Satellite observations throughout the week showed an intense thermal anomaly from continued lava production. No reports of ash plumes or plume heights were received this week.

If activity continues to increase, larger ash clouds that could affect higher-flying aircraft may be produced. The most immediate ground hazard in the vicinity of the volcano includes light ash fall on nearby communities. Previous historical eruptions from Pavlof caused only a few millimeters (about 1/10th of an inch) of ash to fall on King Cove, Nelson Lagoon, Cold Bay, and Sand Point. Mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano are also of concern in the uninhabited areas around the volcano. Satellite and seismic data and eyewitness observations suggest most of the surface lava activity is occurring on the southeast sector of the steep-sided volcano; this suggests that the Pacific Ocean side of the volcano is at most risk from avalanching hot debris.

At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September 1996 and consisted of a several-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft asl on one occasion. However, most ash clouds were below 20,000 ft asl. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft asl on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf

Pavlof volcano is located on the southwestern end of the Alaska Peninsula. Pavlof is a stratovolcano which rises to an elevation of 8262 feet. With almost 40 historic eruptions, it is one of the most consistently active volcanos in the Aleutian arc. Eruptive activity is generally characterized by sporadic strombolian fountaining continuing for a several-month period. The community of Cold Bay is located 60 km (37 miles) to the southwest of Pavlof.

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

The Aviation Color Code was reduced to Yellow and the Volcano Alert Level was reduced to Advisory on Thursday of this week based on observations over several weeks suggesting that volcanic activity had decreased at Clevelend. The thermal anomaly had decreased in intensity and there had been no evidence of ash or gas plumes in satellite images since late July. Moreover, AVO received no reports of activity during this time period.

Satellite views were cloudy today. Web camera views were also cloudy.

AVO continues to monitor the volcano closely with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: GREEN
Current Volcano Alert Level: Normal

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.

Steam emissions from Korovin and occasional bursts of low-level earthquakes or volcanic tremor may still occur, but both of these phenomena are typical of background activity for this volcano, which has a long-lived, well-developed hydrothermal system.

AVO Weekly Update

The weekly update from AVO:

Friday, August 31, 2007 11:50 AM AKDT (1950 UTC)

PAVLOF VOLCANO (CAVW#1102-03-)
55°24′57″ N161°53′24″ W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

The eruption of Pavlof Volcano that began August 15th continues. Seismicity has steadily increased over the past week and is characterized by volcanic tremor, frequent explosions, and debris flow signals. Satellite observations throughout the week show an intense thermal anomaly from lava fountaining, lava flow, and collapse of the lava flow front.

A continous volcanic ash and gas plume has been reported by ground observers, pilots, and in satellite images since August 28. The height of the eruption plume has varied but has generally been between 12,000 to 16,000 ft (3.7 to 4.9 km) above sea level (ASL). A more vigorous plume to 20,000 ft (6.1 km) ASL with associated lighting (indicative of volcanic ash) was reported by NWS observers in Cold Bay on August 30 at 21:30 ADT (05:30 UTC on August 31). In response, the National Weather Service issued an Ashfall Advisory and Marine Weather Statement. There were no reports of ash fall and the Advisory was cancelled at approximately 01:00 ADT August 31.

If activity continues to increase, larger ash clouds that could affect higher-flying aircraft may be produced. The most immediate ground hazard in the vicinity of the volcano includes light ash fall on nearby communities. Previous historical eruptions from Pavlof caused only a few millimeters (about 1/10th of an inch) of ash to fall on King Cove, Nelson Lagoon, Cold Bay, and Sand Point. Mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano are also of concern in the uninhabited areas around the volcano. Satellite and seismic data and eyewitness observations suggest most of the surface lava activity is occurring on the southeast sector of the steep-sided volcano; this suggests that the Pacific Ocean side of the volcano is at most risk from avalanching hot debris.

At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September 1996 and consisted of a several-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft asl on one occasion. However, most ash clouds were below 20,000 ft asl. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft asl on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf

Pavlof volcano is located on the southwestern end of the Alaska Peninsula. Pavlof is a stratovolcano which rises to an elevation of 8262 feet. With almost 40 historic eruptions, it is one of the most consistently active volcanos in the Aleutian arc. Eruptive activity is generally characterized by sporadic strombolian fountaining continuing for a several-month period. The community of Cold Bay is located 60 km (37 miles) to the southwest of Pavlof.

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Periodically throughout the week satellite views showed a persistent thermal anomaly at Cleveland’s summit. Web camera views were cloudy all week.

AVO continues to monitor the volcano closely with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano’s most recent significant eruption began in February, 2001 and had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

Intermittent, low-level seismic activity continued at Korovin. Satellite views were cloudy all week.

Korovin has erupted several times in the past 200 years, most recently in 1998. Eruptions typically produce minor amounts of ash and occasional, small lava flows. Ash plume heights could exceed 20,000 ft above sea level. Korovin occasionally produces large steam plumes from its summit.

AVO Weekly Update for 8/24/07

AVO Weekly Update for week of 8/24/07, from AVO:

ALASKA VOLCANO OBSERVATORY
Weekly Update
Friday, August 24, 2007 11:40 AM AKDT (1940 UTC)

PAVLOF VOLCANO (CAVW#1102-03-)
55�24′57″ N161�53′24″ W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Activity at Pavlof has continued to increase throughout the week and we have reports that the steam and ash plume is now exceeding 10,000 ft above sea level (asl). A pilot reported the top of the plume to be 18,000 ft (5500 m) late Thursday afternoon. A height of 13,000 ft (4000 m) was calculated using satellite data from 2210 UTC (14:10 AKDT) yesterday. However, at 0430 UTC August 24 (18:30 AKDT August 23) another pilot reported that the plume was only “a couple thousand feet” above the summit (or approximately 10,000 ft [3000 m] asl) AVO believes that plumes exceeding this height, and perhaps reaching as high as 20,000 ft (6100 m), are likely, but not certain, to occur in the coming days to weeks.

Seismic activity has remained elevated all week at Pavlof, with moderate levels of tremor occurring almost continuously and with occasional bursts of higher amplitude. The average seismic amplitude has increased slowly throughout the week. Many small to moderate explosions have been recorded in the seismic record; lahars flowing down Pavlof’s southeast flank have also been recorded. Satellite data showed strong thermal anomalies at the summit throughout the week as well as occasional ash clouds.

An AVO field crew visited Pavlof August 18 – 19. The crew performed instrument maintenance and made visual and FLIR (thermal) observations of the ongoing eruption. The FLIR confirmed the existence of a new vent about 200 m (650 ft) below the summit on the southeast flank of the volcano. The vent is approximately 50 m (160 ft) across and is feeding a lava flow that, at the time of the observation (August 18), was more than 0.5 km (0.3 mi) long and about 25 m (80 ft) across. The crew also observed a lahar reaching the Pacific coast, incandescent lava, and explosions at the vent that sent 5 m (15 ft) long blocks flying 50 m (150 ft) through the air.

The current episode began at approximately 9:30 UTC (01:30 AKDT) on August 14 with an abrupt increase in seismic activity; AVO raised the alert level and color code to ADVISORY / YELLOW on the afternoon of August 14. Strong thermal anomalies began to appear in AVHRR and GOES satellite data as early as 06:33 UTC August 15 (22:33 AKDT August 14), leading AVO to raise the alert level and color code to WATCH / ORANGE on the morning of August 15.

Immediate hazards in the vicinity of the volcano include light ash fall on nearby communities, mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano. At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September, 1996 and consisted of a 3.5-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft ASL on one occasion. However, most ash clouds were below 20,000 ft ASL. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft ASL on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf

AVO continues to monitor the activity closely; satellite and seismic data are checked frequently around the clock.

Pavlof volcano is a steep-sided, symmetrical, 8261-ft-high stratovolcano located on the southwestern end of the Alaska Peninsula about 590 miles southwest of Anchorage. The community of Cold Bay is located 37 miles to the southwest of Pavlof; Nelson Lagoon, King Cove, and Sand Point are other communities within 75 miles of the volcano. With almost 40 historic eruptions, it is one of the most active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic lava fountaining continuing for a several-month period. Additional hazards in the vicinity of the volcano included light ash fall on nearby communities, mudflows, lava flows and avalanching of hot debris on the flanks of the volcano. For more information on Pavlof and potential volcano hazards, please see our web site:

http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Pavlof

CLEVELAND VOLCANO (CAVW#1101-24-)
52�49′20″ N169�56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Satellite and webcam views were predominantly cloudy all week, though on several occasions thermal anomalies were seen.

Photographs of a small burst of ash rising a few thousand feet above the summit of the volcano on July 20 (posted on the AVO web page http://www.avo.alaska.edu/) illustrate the kind of intermittent activity that is likely occurring. Based on previous historical eruptions of Cleveland, however, sudden explosions sending ash higher than 20,000 ft above sea level remain possible.

AVO continues to monitor the volcano closely with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano’s most recent significant eruption began in February, 2001 and had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52�22′48″ N174�9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

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.

Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 184 km (110 mi) east of Adak, 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 as recently as June, 1998. 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 1907, 1951, 1953, 1954, 1973, 1976, 1986, 1987, 1996, and 1998. All of these eruptions produced 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 9200 m (16,000 to 30,000 feet) above sea level.

AVO Weekly Update for 8/17/07

The AVO Weekly Update for the week of 8/17/07:

ALASKA VOLCANO OBSERVATORY
Weekly Update
Friday, August 17, 2007 2:30 PM AKDT (2230 UTC)

PAVLOF VOLCANO (CAVW#1102-03-)
55°24′57″ N161°53′24″ W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Pavlof Volcano, on the Alaska Peninsula, has been erupting since at least early Wednesday, August 15. AVO is maintaining aviation color code ORANGE and volcanic activity alert level WATCH at this time.

Persistent earthquake activity and flow events, probably lahars (mudflows), continue at Pavlof Volcano. Several discrete explosion earthquakes have also been recorded. Though clouds obscured the volcano in satellite images Friday morning, one GOES satellite image shows that the large thermal feature from the summit eruption persists. These observations show that an eruption of lava at the surface is continuing. While a primary hazard from this eruption is airborne ash, explosions producing ash do not seem to be significant at this time. We have no evidence that ash has exceeded 10,000 ft asl and any ash produced is likely staying below 15,000 ft above sea level.

The current episode began at approximately 9:30 UTC (01:30 AKDT) on Tuesday, August 14 with an abrupt increase in seismic activity. Based on the patterns of unrest leading to past eruptions at Pavlof, AVO raised the alert level and color code to ADVISORY / YELLOW on Tuesday afternoon.

The rate of low frequency earthquakes steadily increased through Tuesday night. Strong thermal anomalies began to appear in AVHRR and GOES satellite data as early as 06:33UTC Wednesday, August 15 (22:33 AKDT Tuesday, August 14) and continued to be observed in all subsequent clear satellite views. AVO raised the alert level and color code to WATCH / ORANGE on Wednesday morning.

Mariners offshore to the east and south observed incandescent blocks of lava tumbling down the east-southeast slopes and fire fountaining on the southeast side of the summit during the predawn hours Wednesday morning. Pilots reported that Pavlof was emitting ash with a plume extending as far as 8 km (5 mi) south-southeast of the summit at an altitude of about 2.6 km (8400 ft) later on Wednesday morning. They also reported that the normally snow-covered volcano was now covered with ash.

Immediate hazards in the vicinity of the volcano include light ash fall on nearby communities, mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano. At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September, 1996 and consisted of a several-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft ASL on one occasion. However, most ash clouds were below 20,000 ft ASL. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft ASL on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf

AVO continues to monitor the activity closely; satellite and seismic data are checked frequently around the clock. An AVO crew is enroute to Cold Bay to install additional monitoring equipment near the volcano.

Pavlof volcano is a steep-sided, symmetrical, 8261-ft-high stratovolcano located on the southwestern end of the Alaska Peninsula about 590 miles southwest of Anchorage. The community of Cold Bay is located 37 miles to the southwest of Pavlof; Nelson Lagoon, King Cove, and Sand Point are other communities within 75 miles of the volcano. With almost 40 historic eruptions, it is one of the most active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic lava fountaining continuing for a several-month period. Additional hazards in the vicinity of the volcano included light ash fall on nearby communities, mudflows, lava flows and avalanching of hot debris on the flanks of the volcano. For more information on Pavlof and potential volcano hazards, please see our web site: http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Pavlof

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Clouds obscured satellite and webcam views of Cleveland all week. On Sunday, a commercial pilot observed that Cleveland was not steaming and showed no other signs of activity.

Photographs of a small burst of ash rising a few thousand feet above the summit of the volcano on July 20 (posted on the AVO web page http://www.avo.alaska.edu/) illustrate the kind of intermittent activity that is likely occurring. Based on previous historical eruptions of Cleveland, however, sudden explosions sending ash higher than 20,000 ft above sea level remain possible.

AVO continues to monitor the volcano closely with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano’s most recent significant eruption began in February, 2001 and had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.

AVO Weekly Update for 8/17/07

The AVO Weekly Update for the week of 8/17/07:

ALASKA VOLCANO OBSERVATORY
Weekly Update
Friday, August 17, 2007 2:30 PM AKDT (2230 UTC)

PAVLOF VOLCANO (CAVW#1102-03-)
55°24′57″ N161°53′24″ W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Pavlof Volcano, on the Alaska Peninsula, has been erupting since at least early Wednesday, August 15. AVO is maintaining aviation color code ORANGE and volcanic activity alert level WATCH at this time.

Persistent earthquake activity and flow events, probably lahars (mudflows), continue at Pavlof Volcano. Several discrete explosion earthquakes have also been recorded. Though clouds obscured the volcano in satellite images Friday morning, one GOES satellite image shows that the large thermal feature from the summit eruption persists. These observations show that an eruption of lava at the surface is continuing. While a primary hazard from this eruption is airborne ash, explosions producing ash do not seem to be significant at this time. We have no evidence that ash has exceeded 10,000 ft asl and any ash produced is likely staying below 15,000 ft above sea level.

The current episode began at approximately 9:30 UTC (01:30 AKDT) on Tuesday, August 14 with an abrupt increase in seismic activity. Based on the patterns of unrest leading to past eruptions at Pavlof, AVO raised the alert level and color code to ADVISORY / YELLOW on Tuesday afternoon.

The rate of low frequency earthquakes steadily increased through Tuesday night. Strong thermal anomalies began to appear in AVHRR and GOES satellite data as early as 06:33UTC Wednesday, August 15 (22:33 AKDT Tuesday, August 14) and continued to be observed in all subsequent clear satellite views. AVO raised the alert level and color code to WATCH / ORANGE on Wednesday morning.

Mariners offshore to the east and south observed incandescent blocks of lava tumbling down the east-southeast slopes and fire fountaining on the southeast side of the summit during the predawn hours Wednesday morning. Pilots reported that Pavlof was emitting ash with a plume extending as far as 8 km (5 mi) south-southeast of the summit at an altitude of about 2.6 km (8400 ft) later on Wednesday morning. They also reported that the normally snow-covered volcano was now covered with ash.

Immediate hazards in the vicinity of the volcano include light ash fall on nearby communities, mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano. At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September, 1996 and consisted of a several-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft ASL on one occasion. However, most ash clouds were below 20,000 ft ASL. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft ASL on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf

AVO continues to monitor the activity closely; satellite and seismic data are checked frequently around the clock. An AVO crew is enroute to Cold Bay to install additional monitoring equipment near the volcano.

Pavlof volcano is a steep-sided, symmetrical, 8261-ft-high stratovolcano located on the southwestern end of the Alaska Peninsula about 590 miles southwest of Anchorage. The community of Cold Bay is located 37 miles to the southwest of Pavlof; Nelson Lagoon, King Cove, and Sand Point are other communities within 75 miles of the volcano. With almost 40 historic eruptions, it is one of the most active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic lava fountaining continuing for a several-month period. Additional hazards in the vicinity of the volcano included light ash fall on nearby communities, mudflows, lava flows and avalanching of hot debris on the flanks of the volcano. For more information on Pavlof and potential volcano hazards, please see our web site: http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Pavlof

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Clouds obscured satellite and webcam views of Cleveland all week. On Sunday, a commercial pilot observed that Cleveland was not steaming and showed no other signs of activity.

Photographs of a small burst of ash rising a few thousand feet above the summit of the volcano on July 20 (posted on the AVO web page http://www.avo.alaska.edu/) illustrate the kind of intermittent activity that is likely occurring. Based on previous historical eruptions of Cleveland, however, sudden explosions sending ash higher than 20,000 ft above sea level remain possible.

AVO continues to monitor the volcano closely with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano’s most recent significant eruption began in February, 2001 and had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.

AVO Weekly Update

AVO weekly update from AVO:

ALASKA VOLCANO OBSERVATORY
Weekly Update
Friday, August 10, 2007 3:55 PM AKDT (2355 UTC)

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Occasionally visible thermal anomalies at Cleveland during the past week indicate that low-level eruptive activity continues. Photographs of a small burst of ash rising a few thousand feet above the summit of the volcano on July 20 (posted on the AVO web page http://www.avo.alaska.edu/) illustrate the kind of intermittent activity that is likely occurring. Based on previous historical eruptions of Cleveland, however, sudden explosions sending ash higher than 20,000 ft above sea level remain possible.

AVO continues to monitor the volcano closely with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

Intermittent, low-level seismic activity continues at Korovin. Cloudy conditions prevented views of the volcano by satellite for most of the past week.

Korovin has erupted several times in the past 200 years, most recently in 1998. Eruptions typically produce minor amounts of ash and occasional, small lava flows. Ash plume heights could exceed 20,000 ft above sea level. Korovin occasionally produces large steam plumes from its summit.

AVO Weekly Update for 7/20-27/07

Alaska Volcano weekly update from AVO:

ALASKA VOLCANO OBSERVATORY
Weekly Update
Friday, July 20, 2007 3:00 PM AKDT (2300 UTC)

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Weak thermal anomalies have been observed at Cleveland volcano in satellite images during periods of clear weather over the past month, and were thought to represent occasional low-level eruptive activity. A much more intense thermal anomaly and an associated steam and gas plume were observed on July 20, 2007 in a satellite image from 1525 UTC (0725 ADT). Although unconfirmed by visual reports, this increase in thermal activity is believed to indicate an increase in the intensity of eruptive activity. No ash emissions have been detected in satellite data since October 2006, but the possibility of an explosion sending an ash cloud to heights in excess of 20,000 ft above sea level has likely increased.

The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions with ash plumes that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

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.

Korovin has erupted several times in the past 200 years, most recently in 1998. Eruptions typically produce minor amounts of ash and occasional, small lava flows. Ash plume heights could exceed 20,000 ft above sea level. Korovin occasionally produces large steam plumes from its summit.

AVO Weekly Update

AVO Weekly Update:

Friday, July 20, 2007 3:00 PM AKDT (2300 UTC)

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch

Weak thermal anomalies have been observed at Cleveland volcano in satellite images during periods of clear weather over the past month, and were thought to represent occasional low-level eruptive activity. A much more intense thermal anomaly and an associated steam and gas plume were observed on July 20, 2007 in a satellite image from 1525 UTC (0725 ADT). Although unconfirmed by visual reports, this increase in thermal activity is believed to indicate an increase in the intensity of eruptive activity. No ash emissions have been detected in satellite data since October 2006, but the possibility of an explosion sending an ash cloud to heights in excess of 20,000 ft above sea level has likely increased.

The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions with ash plumes that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

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.

Korovin has erupted several times in the past 200 years, most recently in 1998. Eruptions typically produce minor amounts of ash and occasional, small lava flows. Ash plume heights could exceed 20,000 ft above sea level. Korovin occasionally produces large steam plumes from its summit.

AVO Weekly Update for the Week of July 6-13, 07

Current AVO Weekly Update

ALASKA VOLCANO OBSERVATORY
Weekly Update
Friday, July 13, 2007 11:30 AM AKDT (1930 UTC)

KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

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.

Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 184 km (110 mi) east of Adak, 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 as recently as June, 1998. 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 1907, 1951, 1953, 1954, 1973, 1976, 1986, 1987, 1996, and 1998. All of these eruptions produced 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 9200 m (16,000 to 30,000 feet) above sea level.

CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory

Partly cloudy satellite views on July 12 showed a weak thermal anomaly but no evidence of ash or other deposits in the summit area. Clouds obscured the summit on other days during the week and AVO has received no additional information about activity at Cleveland Volcano.

Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano’s most recent significant eruption began in February, 2001 and had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.