A seismic-refraction surcey was conducted of the Mono Craters-Long Valley region of eastern California during the month of August, 1982, as part of a multi-disciplinary investigation of the Mono Craters area sponsored by the Office of Basic Energy Science under the Department of Energy. The overall objective of this investigation is to evaluate the Mono Craters structure as a possible site for deep scientific drilling and, in particular, to assess the possibility that a youthful magma chamber may reside inthe upper crust beneath the Mono Craters structure.Full size version of plates available in additional file with the report.