Published on 27-Sep-06

Montserat----27 Sept. 2006---Visual observations show that the dome has continued to grow at a moderate rate during the reporting period, though not as fast as during the first two weeks in September.

Montserrat Volcano Update: Report for 15 to 22 September, 2006

Montserrat---27 Sept. 2006---Visual observations show that the dome has continued to grow at a moderate rate during the reporting period, though not as fast as during the first two weeks in September. Growth appears to have occurred predominantly in the summit area and on the southern and eastern sides of the dome. The vent situated in the Gages Wall is still active, minor explosive activity was observed from the helicopter during a routine observation flight on the afternoon of the 19^thSeptember.

An intense episode of volcanic tremor lasting just half an hour started at 4pm on the 19^th September and this was accompanied by intense rockfall activity giving rise to minor pyroclastic flows down the northern and northeastern flanks of the lava dome. Before that, the last significant episode of volcanic tremor ended early on 16 September.

Seismicity over the reporting period has been dominated by rockfalls with a significant drop in earthquake activity relative to the previous reporting period. The seismic network recorded 279 rock fall signals, 34 long period rockfall signals, 11 long period earthquakes, 17 hybrid earthquakes and 1 volcano tectonic earthquakes during the reporting period.

Measured daily sulphur dioxide flux showed less variation relative to the previous reporting period. Average sulphur dioxide flux for the reporting period was estimated at 232 tonnes/day, varying between 67 tonnes/day on 15 September and 485 tonnes/day on 17 September.

The alert level was reduced to 3 on 21 September.

Residents of Montserrat and visitors to the island are advised to tune into ZJB Radio for up-to-date information on the volcano. Access to all areas south of Richmond Hill, and south of Jack Boy Hill to Bramble airport and beyond is prohibited at all times. The daytime entry zone, comprising the top part of St. George�s Hill, is closed. The maritime exclusion zone around the southern part of the island extends 3 km off shore from Whites Yard to Roches Yard on the east side of the volcano, 2 km offshore from O�Garras to Gingoes on the south-west, and 200 m offshore from Plymouth.

For further explanations of the volcanic phenomena described, and information about the Soufriere Hills Volcano and the ongoing eruption, please look at the MVO website: http://www.mvo.ms.