Montserrat Volcano Observatory


Daily Report
Report for the period 16:00 on 22 Jan. 1996
to 16:00 on 23 Jan. 1996


Nineteen (19) events were located during the period under review. These were mostly long-period earthquakes located at depths of 0 to 2 km beneath the Soufriere Hills volcano. These events have become less frequent but proportionally larger during the period under review. Three small volcano-tectonic earthquakes were located in the southern part of the island. One period of broadband tremor occurred between 16:00 and 17:50 on the 22 January. Fifteen seismic signals of the type associated with rockfall were recorded by the Gages seismograph station. Several of these signals were accompanied by ash emissions and the largest event, which occurred at 12:36 on the 23 January, generated an ash plume that drifted towards the O'Garra's area.

EDM measurements were carried out on the Whites - Castle Peak - Long Ground triangle. The results obtained are within the error of the instrument. A review of the measurements obtained from the Tar River EDM line two days ago reveals that the slant distance has in fact shortened by 2.5cm and not 25cm as reported previously. This is consistent with the slant changes observed for the same period on the Whites- Castle Peak - Long Ground triangle. This triangle essentially measures the same line.

Another day of excellent weather gave scientist very good views of activity at English's Crater. A flight at midday allowed correlation of the 12:36 ash emission with the collapse of the new spine. Debris from this spine has fallen into the southwestern part of the moat area. Several rockfalls were observed from the north side of the dome; these generated small ash clouds and continue to deposit fresh material in the moat area to the north. Steam emission was observed from several areas of the new dome with emission from the northern section being most vigorous.


Montserrat Volcano Observatory