Today activity at the volcano was about the same level as yesterday, with ash venting and a moderate number of rockfall signals. The earthquake count today is taken from the short period network, since the broadband network had a period of down time this morning whilst new radio links were tested. Between 16:00 yesterday and 16:00 today there were 7 hybrid earthquakes, 3 volcano-tectonic earthquakes, 3 long period earthquakes and 117 rockfall signals. The rockfalls occurred throughout the day, but there were two ill-defined peaks in activity at around 3 am this morning and 4 pm this afternoon.
The volcano was clear again today and this confirmed that the active face of the dome remains in the Galways area. Ash venting was occurring from the back of the scar excavated by the 26 December eruption. Ash production continued all day with a plume remaining above the volcano at a height of approximately 2 km. Very light ashfall occurred over a large part of the north of Montserrat. Ash was generated by the many small rockfalls observed going down the Galways side of the dome, but the majority of ash was the result of the ash venting that continued whether rockfalls were occurring or not. A strong smell of sulphur was noted in the Salem area; this is most likely a result of the northerly direction of the wind.
Electronic distance measurements were taken today from Windy Hill to the new reflector on the crater wall above Farrells. This is only the second set of measurements to be taken, and it is too early to determine a trend in the data, but MVO will continue to monitor this flank of the volcano very closely.
Theodolite points were measured on the northern and western faces of the dome complex. These will help to constrain the photographic volume survey that was completed yesterday. A long occupation GPS survey was started between Harris Lookout and Blakes.
MVO continues to upgrade the monitoring network. Today, a radio link from the Windy Hill seismic station to the Observatory via Garibaldi Hill and Silver Hills was established. There are now three operational stations on the broadband network including a three component broadband seismic station. The Centre Hills helipad was extended with the valuable help of the Royal Marines, and concrete bases for tiltmeters were constructed on Gages Mountain and at Hermitage.
Despite the ashfall dust levels at all monitoring stations remained low today.
People should remain alert and listen to Radio Montserrat for further information.