The level of volcanic activity has been low during the past 24 hours. The number of rockfalls has decreased since yesterday, and only a few small ash clouds have been observed.
The small, repetitive hybrid earthquakes that have been recorded since 10 April have now ceased completely. The broadband tremor recorded at the closest seismic stations has been less frequent today. Several moderately sized long-period earthquakes have been recorded, and these are located beneath the crater at uncertain depths.
The eastern EDM triangle was measured today. The measurements show that Castle Peak has moved only slightly since the triangle was last measured, consistent with the long-term movement of 1 mm/day to the northeast. Six lines around the north and east of the volcano were measured using the GPS equipment. The results will be processed overnight.
Further correlation spectrometer (COSPEC) readings were made today. This involves taking measurements of ultraviolet radiation through the steam plume at various locations around Plymouth. The results will be available tomorrow. These measurements will be repeated for at least the next month.
Visual observations have been restricted by low cloud. During brief clearances in the early afternoon, almost-continuous, small rockfalls were observed from the northeast and northern sections of the dome. Some new rocks have been deposited on top of the crater rim at Farrell's Yard, probably as a result of small pyroclastic flows from the northern part of the dome.
Despite a slight decrease in the level of volcanic activity today, the volcano remains in a highly dangerous state, and the scientists urge that visits to the evacuated zone be kept to a minimum. The Tar River, Long Ground and Whites areas are extremely dangerous and should not be entered under any circumstances.