Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 3 June
to 4 pm 4 June 1997
The current alert level is ORANGE

Pyroclastic flows have continued in the Tuitt's Ghaut, and reached further than yesterday. There has been almost continuous activity in the ghaut, with pulses of higher-level activity in the early hours of this morning and this afternoon.

Between 1:30 am and 4 am there were several small pyroclastic flows in Tuitt's Ghaut, which were larger than any recorded previously on the northern side of the volcano. These flows had travelled a distance of 1.8 km from the crater rim, which takes them to the last bend in the ghaut before the long straight stretch that leads to the junction with Paradise River. During the rest of the morning the activity was at a lower level, although there were still small regular pyroclastic flows in the Tuitt's Ghaut.

There were several flows this afternoon, which resulted in almost continuous ash production, with the ash being blown to the west. The flows were not as intense as the morning's activity, and did not travel any further down the ghaut.

Observations of the dome were possible this afternoon during a brief period when the cloud lifted. There is a prominent channel on the northern side of the dome which has been formed by the recent pyroclastic flows in Tuitt's Ghaut. Also, the whole north-eastern side of the dome has started to crumble, and some rockfalls on the eastern face of the dome were seen and heard.

The seismic activity has been about the same in the last 24 hours, with few earthquakes. There were only 5 small hybrid earthquakes and 1 long-period earthquake. A total of 93 rockfall signals were recorded, a slight decrease from yesterday.

COSPEC runs could not be made this morning because of the wind direction. Attempts were made to measure the sulphur dioxide flux from the helicopter this afternoon, and the results will be reported later.

level of earthquake activity remains low, with only 6 hybrid and 5 long-period earthquakes recorded in the last 24 hours. The recorded rockfall activity was about the same as yesterday, with 126 events. The pyroclastic flow activity in the last week has followed a pattern, with most of the activity occurring in a 4 hour period, with a gap of 16 to 20 hours until the next increase in activity. Some pyroclastic flows occur outside the periods on enhanced activity, and there is no guarantee that this pattern will continue. The next period of increased activity is due between 4 and 8 am tomorrow.

A visit was made this afternoon to Chances Peak to carry out GPS measurements and service the accelerometer which is in operation there. The crack on the eastern side of Chances Peak were measured, and there has been further shear movement along the crack of 19 mm since 23 May. This is about the same relatively high rate of deformation as was measured before on this crack.

More pyroclastic flows are expected in Tuitt's Ghaut in the next few days, and it is likely that these flows will travel further than before. The pyroclastic flows will probably be confined to the ghaut, but there is a risk of surge clouds affecting areas along side the ghaut. Mosquito and White's Ghaut could also be a pathway for pyroclastic flows, and there is a chance of surges spilling into Spanish Point. These conditions make the areas of Long Ground, Whites, Tuitt's, Bramble, Bethel, Spanish Point, Farms, Harris, Farrell's, Riley's and Streatham extremely dangerous, and people should not visit these areas. The road alongside the Paradise River between Harris and Farm's Bridge will be blocked.

Montserrat Volcano Observatory