9219541 Meyer Portable arrays of digital seismometers recording passive sources (earthquakes) or active sources (explosions) are capable of imaging buried structure in the crust and mantle. This award will support the development of a new type of portable digital seismograph for field deployment in seismic array experiments of long duration in remote areas where maintenance is difficult and expensive. Some of the desired design features to be incorporated include low power consumption, waterproof, temperature insensitivity, improved timing, and capable of burial against the threat of vandalism. ***