The very small hybrid (3-5 Hz) earthquakes that decreased in amplitude yesterday continued to decrease but were still the dominant feature of the seismic activity. The rate of occurrence remained constant at about 5 to 6 events per minute but these events are now so small that they are only observed at the closest seismometer station (Gages). There were intermitant periods of very low amplitude broadband tremor observed between 18:00 and 22:00 only on the closest station. Several small long-period earthquakes were recorded on the nearest stations to the volcano but two larger long-period earthquakes at 21:14 and 15:26 were recorded throughout the seismic network. They had depths of 1.5 to 2.0 km beneath the volcano and had magnitudes of 2.0 to 2.5. Several small seismic signals recorded by the seismic stations throughout the day are probably the result of rockfalls.
EDM measurements completed today on the Long Ground-Castle Peak-Whites triangle on the eastern flanks of the volcano. Processing of these measurements suggest that there were no changes in line length since this station was last occupied two days ago.
Clear conditions today allowed good views to be obtained of English's Crater from the helicopter. Vertical growth of the northern parts of the dome has brought the top of this area to about level with the highest parts of the old Castle Peak dome. The southern area of active dome growth continues to be essentially horizontal and steam emission from the crater is concentrated within the top central parts of the new dome. An attempt was made to obtain overlapping aerial photographs of the crater; these will be used to provide better estimates of the rate of dome growth.