********************************* Sunday 24 December 2006 - ALERT LEVEL INCREASE - 4 - From: Dr. Vicky Hards <vicky@xxxxxx> ********************************* Ash venting began at around 10:00 (local time), and continued throughout the day from a vent on the western side of the dome, possibly behind Gage's Wall. Ash clouds reached an estimated 10,000 feet. This venting was accompanied by low level tremor becoming noticeable on the MVO seismic network by 11:00, continuing through until about 16:30 before seismicity returned to background levels. At around 17:20 a small pyroclastic flow was observed in the upper reaches of Tyres Ghaut (northwest) and venting became more energetic, possibly hotter, with ash clouds rising more rapidly. At this point the decision was taken to raise the alert level (see www.mvo.ms) to 4. After dark incandescent rockfalls were clearly visible on a sector through from the northwest to west, confirming a switch in the focus of dome groth to the west/northwest. At aound 20:00 a swarm of low-amplitude long-period earthquakes began and continuing until around 00:30 - becoming most intense between 22:30 and 23:30 - before seismicity again returned to backgound levels. ---------------------------------------------- Dr Vicky Hards Director Montserrat Volcano Observatory P.O. BOX 318 Flemmings Montserrat West Indies. Tel: 1-664-491-5647 FAX: 1-664-491-2423 Email: vicky@xxxxxx <mailto:vicky@xxxxxx> http://www.mvo.ms <http://www.mvo.ms/> ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
