The level of activity overnight has remained at about the same as yesterday. A low level of rockfall activity occurred throughout the period. The more distinctive events were a small Volcano Tectonic earthquake swarm and a period of volcanic tremor and near continuous rockfall activity which followed.
The volcano-tectonic earthquake swarm started just before midnight and lasted for about two hours. This swarm was similar to the swarms that have occurred at regular intervals in the past few days. After the earthquake swarm, there was an episode of tremor and then some near continuous rockfall activity that lasted for about 40 minutes.
When the tremor peaked at about 3:30 am a plume with estimated height of about 5000 ft above sea level was seen above the crater in the moonlit night. There were no reports of ashfall. A late reconnaissance flight to the volcano late yesterday evening revealed that the recent ash flows produced very little change to the physical configuration of the lava dome. It was confirmed that the flows originated from the area of new growth. More debris had accumulated at the base of the dome and inside the chutes leading from it.
The south-eastern face of the dome is still unstable, and expected to collapse soon, causing pyroclastic flows in the Tar River Valley. Residents are reminded to wear ash masks if there is ash in the air. The Tar River and upper Galway's areas are extremely dangerous, and should not be entered under any circumstances. Zone E, which includes Corkhill and the airport, remains safe at this time.