Marvin R. Couchman Seth C. Moran Andrew B. Lockhart Kelly J. Swinford Richard G. LaHusen David R. Sherrod William E. Scott Peter H. Stauffer Patrick J. McChesney 2008 The instruments in place at the start of volcanic unrest at Mount St. Helens in 2004 were inadequate to record the large earthquakes and monitor the explosions that occurred as the eruption developed. To remedy this, new instruments were deployed and the short-period seismic network was modified. A new method of establishing near-field seismic monitoring was developed, using remote deployment by helicopter. The remotely deployed seismic sensor was a piezoelectric accelerometer mounted on a surface-coupled platform. Remote deployment enabled placement of stations within 250 m of the active vent. application/pdf 10.3133/pp17507 en U.S. Geological Survey Seismic-monitoring changes and the remote deployment of seismic stations (seismic spider) at Mount St. Helens, 2004-2005 reports