MOUNT CLEVELAND VOLCANO CONTINUES BUILDING MASSIVE DOME
GW RASTOPSOFF, ALASKA NATIVE NEWS
PUBLISHED 09/07/2011 – 7:18 A.M. AKST
CHUGINADAK ISLAND, ALASKA-Mount Cleveland, a strato-volcano perched on Chuginadak island, has had its Volcano Alert status raised back up to “Watch” and its Aviation code re-raised to “Orange.”
This comes as observations of the volcano yesterday that the small lava dome in the summit crater has resumed growth and now fills the floor of the crater.
A persistent thermal anomaly has been observed since September 3, probably marking the timing of resumed lava dome growth. The size of the dome as of August 30 when it appeared to have stopped growing was approximately 262 feet in diameter. The current dome is approximately 394 feet in diameter. If dome growth continues, lava flows onto the flanks of the volcano may develop but would not be hazardous to aviation. The presence of the lava dome increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. Short-lived explosions could produce an ash cloud that exceeds 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours.
The team at the Alaska Volcano Observatory were unsure on September 2nd, whether the 6.8 earthquake had disturbed the apparent rest of the volcano. But, satellite information began to trickle in on the next day as the first of the anomalies since the down-grade of the volcano made itself known. That information had the volcano obscured by cloud cover so no determination could be made then. It wasn’t until yesterday that a better view of the summit of the volcano could be seen.
Although no connection has been made, the 6.8 earthquake and its numerous after-shocks felt on and after September 2nd, may very well have been responsible for the current activity at Mount Cleveland.
There was another after-shock from the September 2nd quake again early this morning at 2:36 am measuring 4.4 magnitude.