Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 2 November
to 6 pm 3 November 1997

Activity at the volcano has been at a relatively high level today with semi-continuous ash venting, pyroclastic flows and hybrid earthquake swarms.

Ash venting has been taking place for most of the day although for the earlier part of the day it was less intense than yesterday, but increased later during the day. The ash venting was first observed at 03:15 am this morning, between hybrid swarms, and produced ash clouds to just over 5,000 ft. Strong easterly winds have produced extensive ashfall over Plymouth and environs. The venting was seen to occur in pulses coincident with the hybrid earthquakes. Some rockfalls have occurred from the October 22 dome down Tuitts Ghaut. The pyroclastic flows which occurred down the Galways side of the dome have deposited material over most of the fan created by the earlier explosions. These events are apparently triggered by hybrid earthquakes shaking the dome.

Brief glimpses of the dome indicate that the October 22 dome has two summits oriented in a NNE - SSW direction and growth appears to be more in an outward or northerly direction rather than gaining height. The dome also appears too be very blocky and measurements indicate that the more northerly of the two of these summits has not increased in height since yesterday. The ash venting is considered to be coming from the south summit region. The Galways side of the pre-explosion dome appears to have changed extensively with two large scars cut into the wall leaving a large and unstable ridge in the wall. It is not yet clear whether the newer material from the October 22 dome is spilling into Galways.

There has been one hybrid swarms during the reporting period which started at10:30 am on the 2 nd November and was continuing up to the time of this writing. There have been a total of 765 hybrid earthquakes during the reporting period. The events are similar in size to those at the start of the swarm. Scattered throughout the day - both during and outside of the hybrid swarms - there were 11 long period earthquakes and 1 volcano tectonic earthquake.

The level of activity on the volcano has been steadily increasing over the past few days. The MVO considers that the volcano is currently in an extremely dangerous state and more explosions or pyroclastic flows could occur at any time. Areas such as the Belham valley, around Trants and the airport are under a very real threat of being impacted by large pyroclastic flows. Under no circumstances, even for brief periods, should anyone be visiting these areas. Friths, Old Towne and Salem are also not safe. Anyone remaining in these areas is strongly urged to move out of the exclusion zone. Indeed any ghaut leading away from the volcano is especially dangerous because of the possibility of hot mudflows travelling down the valleys after heavy rainfall in higher regions. Stay tuned to Radio Montserrat for further information.

Montserrat Volcano Observatory