Subsurface monitoring of tectonic processes and the prediction of volcanic eruptions has obvious societal as well as scientific importance. DOSECC installed instrument packages containing borehole strain meters and three-component seismometers at three sites around Mauna Loa volcano on the Island of Hawaii and on the island of Montserrat.

Current technology for borehole strainmeters and tiltmeters can detect strain and tilt changes of less than 1 part per billion over periods from milliseconds to months allowing for both detection of volcanic events at great distances and a temporally complete record of volcano deformation. These instruments provide substantially better data than continuous GPS systems which have relatively poor resolution (at best ~3mm horizontal, ~10mm vertical), are contaminated by long period noise (e.g., 20-minute period multipath noise), and present data reduction complexities that make real-time analysis of the results difficult and unreliable.

Borehole seismometers likewise obtain improved data resolution by avoiding surface noise. Observations of Long Period events in the Long Valley Caldera suggest that similar events related to magma movement in Hawaii may be recorded by a borehole seismometer, located at a depth of several hundred meters, with noise levels 1000 times below surface values. Observation of these events for volcano monitoring is a critical element in the Volcano Hazards Program priorities.