Montserrat Volcano Observatory

Morning Update
Report for the period 16:00 11 September
to 07:00 12 September 1996

The level of activity at the Soufriere Hills volcano during the night has remained about the same as that observed during the previous reporting period. The seismicity continues to dominated by volcano-tectonic earthquakes and rockfalls. One sequence of volcano-tectonic and small hybrid earthquakes was recorded from 19:35 to 23:55 yesterday 11 September. Preliminary estimates again suggest that these events are located at shallow depths beneath the volcano, similar to other recent VTs. The rockfalls, which were small to moderate in size, occurred throughout the period, with slightly higher activity from 01:20 to 03:30 this morning. Intermittent broadband tremor occurred on the closest seismic stations throughout the update period.

The volcano remained shrouded in cloud during the early morning.

Further rockfalls and pyroclastic flows will occur but all indications at the moment are that the pyroclastic flows will be confined to the Tar River Valley area. However, areas affected by associated ashfalls will obviously depend on the direction and strength of the wind at the time. Extreme care should still be taken when driving in ash affected areas. Dust masks should be worn at all times in ashy environments.

The Tar River Valley and surrounding areas are extremely hazardous and should not be entered under any circumstances.

Montserrat Volcano Observatory