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 29 long-period earthquakes were recorded by most of the stations in the network, along with several signals generated by rockfalls. Three small volcano-tectonic earthquakes occurred, and were located at depths less than 3 km under St George's Hill and Windy Hill.
The eastern EDM triangle, Long Ground - Whites - Castle Peak, was measured today. Only small changes were detected in the line lengths since yesterday.
During a helicopter trip late yesterday afternoon, a spine was seen in the southwest of the dome for the first time, and activity was concentrated in this area. A team visiting Chances Peak this afternoon observed recent growth on the section of the dome just behind the old Castle Peak dome. The height of that section of the dome is estimated to be equal to that of Castle Peak.
Gas and particle samples were collected from Chances Peak and from sites in Plymouth today.