The beautifully symmetrical Mount Cleveland stratovolcano forms the western half of the uninhabited Chuginadak Island in the eastern Aleutians, connected to the eastern half of the island by a narrow isthmus. It is one of the regions most active volcanoes, but at present has no seismic network. Monitoring of its activity is largely based on satellite observation.
Eruption plume from Cleveland yesterday (AVO / USGS)
After the initial explosion 2 days ago, continuous small eruptions produced a steam and ash plume yesterday and decreased in intensity again today. The activity of the volcano, which is not monitored on ground, was detected by satellite data and infrasonic tremor measured by ground-coupled airwaves on the nearby Okmok seismic network, 120 km (80 mi) to the northeast. ...plus
A faint plume extended eastward below 15,000 ft. Satellite data also continue to show highly elevated surface temperatures at the summit. Sudden explosions of blocks and ash are possible with little or no warning. Ash clouds, if produced, could exceed 20,000 feet above sea level. [moins]
A possible explosion occurred this morning at the volcano at 5:00AM AKDT (13:00 UTC) by AVO infrasound recorders. The infrasound signals suggest that this was a relatively short duration, low-level explosion. No eruption cloud has been detected in available satellite views. AVO received no other reports of activity. (USGS / AVO)
AVO lowered the alert level from ORANGE to YELLOW: The summit lava dome extruded in late January 2013 has remained unchanged since the last color code change on February 6, 2013. ...plus
Anomalous surface temperatures prevalent in late January through mid-February declined and the last thermal anomaly observed in satellite imagery was reported on February 26. Although satellite viewing conditions at Cleveland are typically cloudy, clear views between March 1 and 5 indicate no change has occurred in the summit dome and thermal anomalies no longer are present. Therefore, the Aviation Color Code and Volcano Alert Level for Cleveland is lowered to YELLOW/ADVISORY. (Source: AVO) [moins]
After finding evidence of a new lava dome growing in the summit crater, AVO raised the alert level of Cleveland back to orange. ...plus
The decision was based on satellite obtained on 30 Jan that indicate that a lava dome has grown in the summit crater. As of January 30 the dome was about 100 m in diameter and may have begun forming as early as January 24 when elevated surface temperatures were observed in satellite images. The size and shape of the dome appears to be unchanged through February 2 according to the most recently available satellite data. AVO has received no reports of activity or ash emissions since elevated surface temperatures were first observed around the 24th of January. [moins]
