Activity at the volcano has continued at a low level for the last 24 hours although the number of rockfalls has increased slightly. Good views of the dome were obtained from the helicopter and various points around the volcano. No obvious changes were visible in the dome but several small rockfalls produced ash clouds that drifted over Plymouth.
The seismic activity today was very low with only 2 volcano-tectonic, 1 long period and 6 hybrid earthquakes recorded by the network. However, the rockfall activity has increased with 34 rockfall signals recorded, the largest of which produced small ash clouds that drifted to the west over Plymouth.
Good views of the dome from the helicopter this morning revealed that there had been no obvious changes since 3 March. Upward growth of the dome in this period seems to have slowed relative to the period in late February. However the active eastern face continues to be steep and unstable. The north face of the dome appears to be eroding, but Galway's Wall showed little change. A few small rockfalls were observed from the pre-September dome above Galway's Wall during the afternoon.
WESTNET, the GPS network that extends between points on the western flank of the volcano, was measured today. The results are currently being processed.
EDM measurements were conducted on radial lines between Windy Hill and Farrells and between St George's Hill and Farrells. The former line showed an increase of 4 mm since it was last measured on 27 February, and the latter line showed a decrease of 2mm over the same period. Thus there is no consistent trend in these results. Measurements were also made on the Galway's to Chances Peak line after the Chances Peak reflector had been cleaned of ash. This line has shortened by 1.5 cm since it was last measured on 17 February.
Theodolite measurements were made on points on the northern and eastern faces of the dome from both Harris Lookout and Whites. Regular measurements of these points will help to determine whether there is significant change in the dome faces.
COSPEC measurements were made this morning on the traverse along the western flank of the volcano. The results are currently being processed.
The volcano remains active and potentially dangerous. The dome is currently larger than ever before, and shows signs of becoming more active. The situation could worsen over a period of a few hours, and so it is dangerous to spend the night in the evacuated areas. People entering Zone C are reminded to remain alert at all times, and spend the minimum possible time in the evacuated zone. Residents should be reminded that at this current level of alert persons should not be permanently residing in Zones A, B or C. The ash levels in Plymouth can be hazardous, and so it is essential to wear a mask when there is ash in the air. The Tar River Valley and the upper Galway's area are very dangerous and should not be entered at any time.
Prof. Saunders (SRU), Dr. Tony Reedman (BGS) and Mr Lloyd Lynch (SRU) arrived today for a brief visit, and Dr. Paul Jackson and Mr Godfrey Almorales (both SRU) arrived for longer tours of duty.