The level of activity overnight has remained at about the same as yesterday. Low level rockfall activity occurred throughout the period. Also, the recent pattern of small volcano tectonic earthquake swarms followed by a period of volcanic tremor and near continuous rockfall activity continued during the observation period.
A period of high amplitude volcanic tremor followed a volcano-tectonic earthquake swarm which started at about 2:16 yesterday. The tremor started at about 5:30 pm and lasted about 60 minutes. Another VT swarm started at around 4:30 am this morning and is still ongoing. If the recent pattern is followed an episode of tremor will follow and peak at about 8:00 am today. The tremor will also produce some ash.
A late afternoon reconnaissance flight to closely inspect the tremor activity yesterday revealed that the action was focused in an area above Castle Peak. Small quantities of highly fluid lava occasionally flowed from the area. It is quite likely that the tremor is produced as the fluid is pushed to the surface of the dome. Some small ash flows were also generated.
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.