The ongoing eruption of Mount St. Helens continues!  Extrusion of lava in the crater continues at the rate of roughly a pickup truck load per second.  A new smooth area (a slab) is emerging from low on the talus pile of spine 7 to the north of previous areas of extrusion.  The talus pile is now being pushed to the north slightly and is encroaching on the 1980-1986 lava dome.  The inference that the rate of extrusion continues at roughly the same pace is based on visual estimation of the extrusion rate from still images produced by fixed cameras stationed on the crater rim. 

There have been few to no large earthquakes recently.  The drum beats earthquakes continue, but they are very small, barely detectible.  They are only being picked up by the seismometers inside the crater. 

A new special use permit has been signed by the Gifford Pinchot National Forest that will allow UNAVCO to drill four shafts within the National Volcanic Monument and install boreholes strainmeters in each of them.  UNAVCO is a consortium of research institutions, and its mission is to support and promote earth science by advancing high-precision techniques for the measurement and understanding of deformation. The four strainmeter sites are near Windy Ridge, the Fossil quarry site on the southwest side of the volcano, near Marble Mountain Snowpark and at the west end of Johnston Ridge. 

Borehole strainmeters measure strain change by very accurately sensing change in the shape of an instrument cemented into rock. A borehole strainmeter is used to measure underground rock mass deformations (earth strain). It allows direct measurement of both earth dilatational strains and shear strains.  Because the dimensions of the instrument are only a few inches, very precise measurements are required. A typical signal is 10 nanostrain = 0.000 000 001mm across the instrument. In order to avoid noise introduced by thermal effects, wind, and human activity, borehole strainmeters are usually installed several hundred meters below the ground surface. Even at these depths, the instruments are subject to many effects which cause the signal to drift. So they achieve their highest precision for periods shorter than a few weeks.