Seismic activity beneath the volcano has remained at about the same level during the last 24 hours. Dome growth continues, accompanied by only a small number of earthquakes. About 20 long-period earthquakes were recorded by most of the stations in the network, along with several signals generated by rockfalls on the dome. Two small volcano-tectonic earthquakes occurred last night. These were located at about 2 km beneath Harris's.
The eastern and southern EDM triangles were measured today. Only small changes were detected in the line lengths since these triangles were last measured. The measurements show that Castle Peak and Chances Peak continue to move slowly, at rates of less than 2 mm per day.
No visual observations of the crater area were possible today because of the low cloud.
Gas and particle samples were collected again last night and today, from stations at the Gages seismic station, Upper Amersham and the centre of Plymouth. The samples will be taken to England next week for analysis, and the results will be available in about two weeks.