DTM’s Alan Linde, Brian Schleigh, and Michael Acierno returned late last month from Montserrat, where they completed software and hardware modifications to the borehole strainmeter network that the group is operating in the vicinity of the Soufriére Hills Volcano.

At one of the borehole sites (Trants), a pyroclastic flow from the volcano in February of this year pushed the shoreline several hundred meters seaward of the station (see accompanying photo) and resulted in a change in tidal signals seen by the strainmeter.  With colleagues from the Montserrat Volcano Observatory, the DTM team installed a tide gauge at the station.  Data from the tide gauge will allow for an improved understanding of how ocean tides deform the rock in the vicinity of the borehole.  Analysis of previous collapse events at the volcano summit indicates the importance of monitoring barometric pressure at a sample rate greater than the earlier default rate of one sample per second.  Modifications made during the trip increased the sampling rate for barometric pressure to 50 samples per second.