Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 04 April
to 16:00 05 April 1997
The current alert level is ORANGE

The level of volcanic activity has been lower today. There have been a few volcano-tectonic earthquakes and the level of rockfalls has been the same as yesterday.

A total of 19 volcano-tectonic and 3 long-period earthquakes were recorded during the reporting period. 10 of the volcano-tectonic earthquakes could be located and occurred below the crater between depths of 2 and 3 km. These were generally a lot smaller than the earthquakes in yesterday's swarm. There has been a continuation of rockfall and pyroclastic flow activity, with 27 signals recorded by the seismic network. This is the same number as yesterday. There has been intermittent low amplitude tremor on the Gages seismometer, and a large distant earthquake was also recorded by the network.

The volcano has been shrouded with low cloud all day, so good views of the crater area have not been possible. However, in a brief break in the cloud, vigorous steaming was seen on the northern face of the dome.

COSPEC results from yesterday showed a marked increase in the amount of sulphur dioxide in the volcanic plume. The average of the four runs yesterday gave a value of 537 tonnes/day which compares with only 160 tonnes/day one week ago. Attempts were made to measure the sulphur dioxide flux again today, but the wind was blowing towards the south and therefore measurements were not possible.

Despite the apparent lower level of volcanic activity further pyroclastic flows could occur at any time and MVO urges everybody to stay alert. Nobody should sleep in zones A to D tonight, which includes Plymouth, St Patrick's, the central corridor, Harris', Long Ground, Spanish Point and Richmond Hill. Zone E, which includes Corkhill and the airport, remains safe at this time.

Montserrat Volcano Observatory