Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 5 June
to 4 pm 6 June 1997
The current alert level is ORANGE

The situation at the volcano is extremely serious and further pyroclastic flows are expected in Tuitt's Ghaut. These flows are likely to extend even further than the flows which were generated yesterday. We strongly urge anyone still in the revised no-go area which includes Tuitt's, Bramble Village, Bethel, Spanish Point, Farms and Harris to leave immediately. Pyroclastic flows and surges are extremely hot and travel at very high speeds, they may occur with no notice and cannot be outrun.

Following a period of elevated pyroclastic flow activity between 3.00am and 8.00am this morning, the level of activity today has been relatively low. However, there have been regular rockfalls and small pyroclastic flows throughout the day and an increase in the level of activity is expected shortly.

Seismic activity at the volcano has remained low during the last 24 hours although there has been a slight increase in the number of hybrid events. There were a total of 11 hybrid earthquakes of which 8 triggered rockfalls. There were 4 significant long period earthquakes and there were also a number of smaller long period events which didn't trigger the system. Nevertheless, some of these smaller events caused small rockfalls most of which occurred before 8.00am. The number of rockfalls and pyroclastic flows recorded during the last 24 hours is 90, a decrease from yesterday back to the levels of the previous few days.

Visibility was very poor throughout the day with dense cloud sitting below the base of the dome. Observations of the pyroclastic flow and surge deposits in Tuitt's Ghaut were made for the first time from the helicopter today. The front of the pyroclastic flow deposit, which is composed of coarse debris and is marked by a pile of logs, has travelled about 2.7km down the Ghaut. The associated surge has travelled a further 100-200m and is only 200m from the junction with Paradise River. Vegetation has been completely stripped from the valley sides in the upper few hundred metres of the Ghaut. In the base of lower parts of Tuitt's Ghaut there are one or two burned trees still standing and extruding from the deposits. Where the Ghaut is straight, surge deposits do not extend more than 10m beyond the margins of the pyroclastic flow deposit, but at bends in the Ghaut, the surge has ridden high up the Ghaut sides in a 'bobsleigh' effect. Deposits in the upper 1km of the Ghaut are thick and composed of numerous small volume lobate flows. The notch through which material is being fed to Tuitt's Ghaut from the dome is now flared at its top and constricted at the bottom and is filling with rockfall talus from the dome.

Four COSPEC runs were made today and although first estimates suggest a slight reduction in the SO2 flux compared to the last few days.

An EDM survey of the St Georges andWindy Hill area was carried out today and results will be processed tomorrow.

Zones A and B are very dangerous and nobody should be in these areas. Activity is expected to increase again this evening and pyroclastic flows could easily extend beyond their previous limit just below Bramble village. We strongly urge anyone in the revised no-go area to leave immediately.

Montserrat Volcano Observatory