Montserrat Volcano Observatory

Daily Report
Report for the period 5 p.m. 23 September
to 5 p.m. 24 September 1998

The volcano has been a little more active today, with a series of small pyroclastic flows generating ash clouds this afternoon.

The seismic network recorded 5 volcano-tectonic earthquakes, 1 hybrid earthquake and 3 rockfall signals over the past 24 hours. A pyroclastic flow signal started at 2:18 pm today and lasted for just over 30 minutes. A rapidly-rising ash cloud was generated above the Gages valley and ash was blown out to sea over Plymouth. The top of the ash cloud is estimated to have risen to 7,000 to 10,000 feet, although some reports from pilots give somewhat higher altitudes.

Observations made from the helicopter suggest that the pyroclastic flows occurred in the upper Gages valley and in the 3 July scar area. The flows moved a maximum of 1 km from the dome. Ash and steam venting continued at an elevated level for an hour or so after this collapse, and a low-level ash plume extended many miles out to sea.

This collapse is similar to previous ones over the past few months, and occurred without warning. It may have been due in part to the large amount of water which would have percolated through the dome after the hurricane.

Residents of Montserrat should continue to check Radio ZJB in case of further sudden developments in the state of the volcano.

Montserrat Volcano Observatory