Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 03 June
to 16:00 04 June 1996

Volcanic activity at the Soufriere Hills volcano has been at a moderate level today, dominated by small to moderate-sized rock fall signals.

Seismicity at the volcano continues to be dominated by the occurrence of rock fall signals which have continued to show a reduction in numbers since yesterday. The total number of rock falls was 27 with the largest being recorded at 04:13, 10:34 and 12:16 on 4 June. No ashfalls were reported from any of these events. There were 14 hybrid events today and two long period earthquakes. Low-amplitude broadband tremor has been intermittent and variable throughout the period. There was one period of near-continuous high frequency tremor between 23:10 on 3 June and 04:00 on 4 June.

Viewing conditions were generally poor for most of the day although there were brief periods during the day when the cloud base lifted and some good views were obtained of the dome. Activity has decreased on the eastern parts of the dome with very few rockfalls observed. The size and shape of the main features on this segment of the dome do not seem to have changed since yesterday. The main areas of dome growth now appear to be the south and western parts of the dome with rock falls and emission of volcanic gas observed from these areas. There are no prominent spines at the top of the dome and the area have become flatter and less rounded than it has been in the past. One small, but prominent spine was seen protruding from the northeastern flank of the dome.

EDM lines at Dagenham, Amersham and Chances Peak steps on the western flanks of the volcano and the Eastern EDM triangle to Castle Peak were measured today. The line lengths to Castle Peak have shortened by 2 to 8 mm since they were last occupied on the 31 May. Dry tilt levelling lines at Brodericks were remeasured today for the first time since 5 January. The results from these measurements are currently being processed. GPS measurements were again hampered by technical problems; measurements would be resumed when the necessary replacements arrive.

Attempts to conduct FTIR measurements directly to the dome was hampered by low cloud cover. COSPEC measurements of SO2 gas concentration in the volcanic plume were made along the coastal road in Plymouth today. The results of these measurements are presently being processed.

Scientists at the MVO view the situation at the Soufriere Hills Volcano with serious concern and urge that visits to the evacuated zone should be kept to a minimum. The Tar River, Long Ground and Whites areas are extremely dangerous, and should not be entered under any circumstances. Given the frequent occurrence of pyroclastic flows in the Tar River valley persons entering this area put themselves at direct risk of serious injury and death.

Montserrat Volcano Observatory