Data from deformation-monitoring instruments indicated that during 28 November-4 December lava-dome growth at Mount St. Helens continued. Small inflation-deflation events occurred which were interpreted as dome-growth pulses. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. A GPS receiver on the W part of the active spine showed continued SW advance at a rate of 3-4 mm per day since September 2007. An image from a camera on the NE flank from 28 November showed no notable landscape changes. Clouds occasionally inhibited visual observations.
Source: US Geological Survey Cascades Volcano Observatory (CVO) – “Report provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”