Seismic activity at the volcano has decreased slightly since yesterday. The small, repetitive hybrid earthquakes are still being recorded, at a rate of slightly less than 1 per minute. Near-continuous low-to-moderate amplitude broadband tremor was recorded between 17:00 on 23 April and 01:00 on 24 April and between 10:30 and 12:00 on 24 April. Shorter bursts of tremor were recorded at other times. Rockfalls and small explosion signals have been recorded throughout the day. Many of these had associated ash clouds which drifted over the Upper Gages area. The largest explosions occurred at 02:07 and 15:08 on 24 April.
The GPS programme continues and further measurements were made today.
MVO has started a programme to investigate the structure of the dome. A preliminary geological map has already been drawn up. The dome is also being surveyed using a variety of techniques..
Observations of the volcano have been possible at times during the day, from the ground and during two helicopter inspections. The rockfalls seem to be concentrated on the northeastern flank of the dome and originate from the base of the last spine, which has fallen over onto the north-eastern flank. A new small spine was observed close to where the last spine emerged. This new spine has many fractures. The general level of steam production is high, and there is vigorous steaming from the base of the south-west flank of the dome.
The volcano is still at a relatively high level of activity. People must limit the time they spend in the evacuated zone to a minimum. The Tar River, Long Ground and Whites areas are extremely dangerous and should not be entered under any circumstances.