Cleveland Activity - Color Code UNASSIGNED : Alert Level UNASSIGNED

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

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.

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.

No significant ash plumes have been observed during this recent episode of increased activity at Cleveland. However, a sudden explosion sending ash higher than 20,000 ft above sea level could still occur.

AVO staff working in Nikolski this week could not see the volcano because of poor weather.

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 ash explosions could occur without warning and may go undetected on satellite imagery.

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 ash explosions could occur without warning and may go undetected on satellite imagery.

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 ash explosions could occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.

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 ash explosions could occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.

AVO is raising the aviation color code to Orange and the volcanic activity alert level to Watch.

Short-duration eruptions such as this have been typical of Cleveland over the last several years. This is the fourth such known eruption this year, the previous one having occurred on August 24. There is no real-time seismic network on Cleveland; AVO monitors Cleveland chiefly by satellite.

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 ash explosions could occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.

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 ash explosions could occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.

There is no real-time seismic network at Cleveland and AVO is unable to track local earthquake activity that may indicate volcanic unrest. Short-lived ash explosions may occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.

Cleveland volcano has produced brief, explosive eruptions sending ash clouds to elevations of 10,000 to 20,000 ft ASL on at least five occasions since February 2006 with the most recent confirmed explosion occurring on August 24, 2006. Additional short-lived, low-level ash explosions (less than 10,000 feet ASL) could continue intermittently for months or years.

There is no real-time seismic network at Cleveland and AVO is unable to track local earthquake activity that may indicate volcanic unrest. Short-lived ash explosions may occur without warning and may go undetected on satellite imagery. Should significant activity send ash above 20,000 feet, detection by satellite is more likely.

Cleveland volcano has produced brief, explosive eruptions sending ash clouds to elevations of 10,000 – 20,000 ft ASL on at least five occasions since February 2006 with the most recent confirmed explosion occurring on August 24, 2006. Additional short-lived, low-level ash explosions (less than 10,000 feet ASL) could continue intermittently for months or years.

Cleveland volcano has produced brief, explosive eruptions sending ash clouds to elevations of 10,000 – 20,000 ft ASL on at least five occasions since February 2006 with the most recent confirmed explosion occurring on August 24, 2006. Additional short-lived, low-level ash explosions (less than 10,000 feet ASL) could continue intermittently for months or years.

AVO monitors Cleveland using satellite images. There is no real-time seismic network on the island and AVO is unable to track local earthquake activity that may indicate volcanic unrest. Short-lived ash explosions may continue to occur without warning. Should a more significant ash explosion occur (greater than 20,000 feet ASL), detection by satellite analysis is more likely.

Cleveland volcano does not have a real-time seismic network and therefore we are unable to monitor earthquake activity that may indicate volcanic unrest. The volcano is monitored, however, using satellite images. Frequent cloudy conditions and the small volume of ash clouds produced by these recent explosions, however, make them difficult to detect in satellite data. Larger events (>20,000 feet ASL) could also occur but are more likely to be detected by satellite. The current level of activity poses a hazard primarily to low-flying aircraft and to people on or within a few kilometers or few miles of the island.

On Monday, AVO received video footage of this eruption showing an ash cloud reaching about 10,000 feet ASL and ash fall occurring from the cloud. Additional video footage shows the volcano to be remarkably quiet within an hour of the explosion, with only minor steaming from the summit vent.

Cleveland Volcano has produced brief, explosive eruptions sending ash clouds to elevations of 10,000 – 20,000 ft ASL on at least five occasions since February 2006. Satellite images since the explosion on August 24 show a faint thermal anomaly at the summit, suggesting that unrest at the volcano continues, and further ash explosions are possible without warning. As a result, AVO is elevating the level of concern color code at Cleveland Volcano from unassigned to YELLOW. The current level of activity poses a hazard primarily to low-flying aircraft and to people on or within a few kilometers of the island.

Short-lived, low-level ash eruptions (<10,000 feet ASL), like that observed this past week, could continue intermittently for months to years. Frequent cloudy conditions and the small size of these ash clouds make them difficult to detect using satellite images. Larger events (>20,000 feet ASL), such as those in March and May, could also occur but are more likely to be detected by satellite. Cleveland volcano lacks a real-time seismic network and therefore we are unable to monitor seismic changes that reflect eruptive activity.

Frequently active 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 producing 3 explosive events and 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. Short-lived explosions of ash reaching approximately 20,000 feet above sea level were observed on February 6 and May 23, 2006.