Two long-period events were located today at shallow depth beneath the Soufriere Hills volcano. Numerous other small long-period events have been occurring at a rate of about one every 10 minutes or so during this period; the largest of these are recorded at the Long Ground station as well as on the Gages seismometer. Moderate amplitude broadband tremor died out at about 17:30 on 18 January and has been absent today. A regional event of magnitude 3.0 was located 15 km north of Montserrat at 19:01 on 18 January at a depth of approximately 13 km.
No EDM measurements were completed today due to the low cloud cover which obscured the upper targets around the volcano.
Visual observations were made both this morning and this afternoon from the helicopter. Rock falls were seen from both the northern and southern parts of the new dome, which are the most active areas of growth at present. Good views of the northern part of the dome confirmed the collapse of the spine, which appears to have occurred in two stages, producing the two ash clouds over Plymouth on 18 January. Large blocks could be seen at the base of the rock-fall talus pile which represent parts of the spine. A new spine was observed close to the southern edge of the dome, which is growing slowly and shedding material into the southern moat area. The continued spine growth and rock falls without associated explosive events suggests that the chances of bigger eruptions are extremely small at present, and would be preceded by a substantial change in seismicity. Vigorous steaming continues from several parts of the dome.
Dr William Ambeh and Chandradath Ramsingh departed Montserrat today (19 January) after the end of their tours of duty. Richard Robertson will be acting Chief Scientist of MVO in the absence of Dr Ambeh.