Montserrat Volcano Observatory


Morning Report
Report for the period 4 pm 10 August
to 7 am 11 August 1997


Activity at the volcano overnight has remained at a high level with continued hybrid earthquake activity. The number of rockfalls have increased during the period.

Two hybrid swarms have occurred overnight. The first, occurred between about 4:13 pm and 9:37 pm, and included over 181 events. The second started at 1:21 am and ended at 4:08 am this morning. It involved over 56 events and was much less intense than the first swarm. Rockfall activity increased during the night with over 6 events being recorded.

No clear views of the dome was obtained during the night and early morning but a thick steam plume was visible over the summit from the MVO.

The activity of the volcano has changed and the 12 hour periodicity seen over the last few days has been broken. Views obtained yesterday of the crater suggest the hybrid earthquake recorded during the past 2 days is associated with rapid extrusion of new dome material. Although no explosions have occurred during this current phase of activity, there is no guarantee that further explosions will not take place. Pyroclastic flows have also occurred outside the most probable time period, and so at no time is it safe to enter the exclusion zone, including the Belham river valley.

There is ash in the air in the west of Montserrat and therefore dust masks should always be worn in these areas. Drivers should also be considerate whilst driving in ashy conditions. The Belham River valley is very dangerous and should not be entered. Access to the exclusion zone is completely restricted, and people should stay completely away from all the flanks of the volcano. Everyone should continue to stay alert, and listen to Radio Montserrat for any announcements.


Montserrat Volcano Observatory
From mvo@candw.ag Wed Aug 13 07:57:56 1997 Received: from mtu.edu (root@mtu.edu [141.219.70.1]) by alt.geo.mtu.edu (8.6.10/8.6.10) with ESMTP id HAA09087 for ; Wed, 13 Aug 1997 07:57:55 -0400 Received: from bounce.civil.mtu.edu (root@bounce.civil.mtu.edu [141.219.20.235]) by mtu.edu (8.8.6/8.8.6) with ESMTP id HAA10740; Wed, 13 Aug 1997 07:57:40 -0400 (EDT) Received: from candw.ag (server2.candw.ag [205.160.233.11]) by bounce.civil.mtu.edu (8.6.10/MTU-R1.8) with SMTP id HAA00732 for ; Wed, 13 Aug 1997 07:56:51 -0400 X-Authentication-Warning: bounce.civil.mtu.edu: Host server2.candw.ag claimed to be candw.ag Received: from ts2p4.candw.ag by candw.ag (SMI-8.6/SMI-SVR4) id WAA24324; Tue, 12 Aug 1997 22:58:24 -0500 Received: by ts2p4.candw.ag with Microsoft Mail id <01BCA7BE.CC2C2040@ts2p4.candw.ag>; Wed, 13 Aug 1997 07:59:17 -0300 Message-ID: <01BCA7BE.CC2C2040@ts2p4.candw.ag> From: MVO To: "'_morning report:email'" Subject: MVO morning report, 12 August 1997 Date: Wed, 13 Aug 1997 07:36:22 -0300 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Status: O Montserrat Volcano Observatory Montserrat, W.I. Report for the period 4 pm 11 August to 7 am 12 August 1997 Activity at the volcano has remained at a high level with more hybrid = earthquake swarms. The number of rockfalls has continued to rise. Two hybrid swarms occurred overnight. The first, between 06:52 pm and = 11:50 pm, was especially intense and included some of the highest = amplitude hybrid earthquakes to be recorded so far. The second started = at 05:39 am and is continuing at time of writing. Rockfall activity = increased during the night with approximately 20 events being recorded = between the two hybrid swarms. No clear view of the dome was obtained during the night and early = morning. Hybrid earthquake swarms have continued which are assumed to be = associated with rapid extrusion of new dome material. The small = explosion yesterday demonstrates that further explosions may take place = with little or no warning. Future explosions may be more intense and = longer lasting than those already experienced. If explosions do occur, = the central zone should be evacuated immediately and people in the = northern zone should seek shelter under as strong a roof as possible. = After an explosion small rocks and ash can be expected to fall = everywhere on the island. Ash and falling rocks make driving hazardous. = Ash is present in the atmosphere and masks should be worn outdoors. Further pyroclastic flows are expected on all flanks of the volcano, and = so at no time is it safe to enter the exclusion zone, including the = Belham river valley. Access to the exclusion zone is completely = restricted. The central zone is evacuated over night and people should = not return to their homes until advised to do so. Everyone should = remain vigilant and continue to listen to Radio Montserrat for any = announcements. 07:00, 12 August 1997