The seismic activity has increased slightly over the last 24 hours but is still at a low level. Thirty long-period earthquakes were recorded by most of the stations in the network, along with several signals generated by rockfalls on the dome.
The southern EDM triangle and the lines from Amersham to Chances Peak Steps and Upper Amersham were measured this morning and the eastern triangle this afternoon. Processing of the data from these triangles continues but preliminary results suggest no change in the line lengths.
Visual observations from the crater rim at Farrell's and from the helicopter were made in generally good conditions. Rock falls were seen from the northwestern part of the growing dome and heard from the southwestern part of the dome which currently appears to be the most actively growing area. Measurements to the top of the dome are still being processed - height of the top of the dome and the rate of vertical growth will be reported tomorrow. Several small ash clouds were seen to the west of the volcano following large rock falls in the crater area.
A gas and particle sampler was in operation at the Gages seismic station for much of the day; the samples collected will enable full characterisation of the volcanic plume, which continues to be emitted at a high rate and includes steam as well as volcanic gases and particles.