Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 28 August
to 16:00 29 August 1996

The level of activity at the Soufriere Hills volcano during this reporting was slightly higher than that observed during the previous reporting period. It continues to be dominated by small- to moderate-sized rock avalanches from the flanks of the growing lava dome, especially the eastern flank.

One hundred and two (102) rockfalls, 43 hybrid, 12 long-period and 3 volcano-tectonic earthquakes were recorded. The largest rockfalls occurred at 21:38 and 23:56 on 28 August and 10:23, 11:05 and 13:41 today. The events of 10:23 and 11:05 were associated with small ash clouds. The volcano-tectonic earthquakes were located at depths less than 2 km beneath English's Crater. The hybrid, volcano-tectonic and long-period earthquakes were generally small. Low-amplitude broadband tremor recorded by the seismic stations closest to the crater was intermittent before about 09:00 this morning but became more persistent after this time, and increased slightly in amplitude after about 14:51.

Visibility was generally poor during most of the day although there were brief periods during which the clouds lifted from parts of the dome. Rockfalls were observed occurring mainly on the eastern flank of the lava dome. Variable steam emission was observed from several areas of the dome. Several areas of the eastern dome still look quite unstable.

No EDM measurements were made today. COSPEC measurements made today yielded an SO2 flux of about 119 tonnes per day.

Further rockfalls and pyroclastic flows will occur but all indications at the moment are that the pyroclastic flows 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