Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 15 August
to 16:00 16 August 1996

The level and nature of activity at the Soufriere Hills volcano during this reporting period was similar to that observed during the previous 24 hours. The activity was dominated by small- to moderate -sized rockfalls and a few small pyroclastic flows from the eastern flank of the growing lava dome.

Sixty seven (67) rockfalls, 34 hybrid and 28 volcano-tectonic earthquakes were recorded during this reporting period. The largest rockfalls occurred at 19:55 on 15 August, and 03:54, 08:16 and 15:29 on 16 August. These were associated with small ash clouds which drifted westward over Plymouth and environs. A sequence of volcano-tectonic and hybrid earthquakes was recorded from 17:10 to 18:40 on 15 August. The VTs were located at shallow depths beneath English's Crater. Two episodes of flash flooding in Fort Ghaut were recorded by the Gages seismic station in the form of moderate-amplitude broadband tremor. Intermittent low-amplitude broadband tremor was recorded at the stations closest to the Crater throughout the period , and has been near-continuous at the Gages seismic station since about 12:30 today. One regional earthquake was recorded by the MVO seismic network during this reporting period at 02:00 today. This event had a magnitude of 4.6 on the Richter scale and was located about 80 km east of Montserrat. It was reported felt in Antigua and St. Kitts.

Visibility was generally good during parts of the day. Vigorous steaming was observed from most of the dome. Most of the rockfalls observed originated from the eastern part of the dome.

EDM and COSPEC measurements were not made today.

Further rockfalls and pyroclastic flows will occur but all indications are that these will be confined to the Tar River Valley area. However, areas affected by associated ashfalls will obviously depend on the direction and strength of the wind at the time. People in areas affected by ash falls should exercise great care when driving. Dust masks should be worn in ashy environments.

The Tar River Valley and surrounding areas are now extremely hazardous, and should not be entered under any circumstances. We urge individuals who continue to ignore this advice to think very seriously before making trips to these highly hazardous zones.

Montserrat Volcano Observatory