Analysis of deep seismic reflection and other data from the southern Washington Cascades

This report covers the period 1 Mar. - 31 May 1993. The overall goals of the program task are to provide a final synthesis of six deep seismic reflection profiles and other geological and geophysical data from the southern Washington Cascades region where a probable extensive deep sedimentary basin has been discovered. This deep sedimentary basin is hypothesized from geological, regional magnetotelluric (MT), gravity, magnetic, and seismic reflection data. This report analyzed three seismic reflection profiles acquired by the Morgantown Energy Technology Centers in combination with the extensive MT and other data to outline a probable geological model for a thick conductive section of rocks in the southern Washington Cascades (called the Southern Washington Cascades conductor, SWCC). Earlier MT models suggested that the section consisted of an east-dipping package that extended to depths of as much as 20 km but appeared to surface in the Bear Canyon area near Morton, Washington, and along the axis of the Carbon River and Morton anticlines. Interpretation of the first three DOE seismic reflections approximately confirmed the MT interpretation and added new information on anticlinal structures and detailed stratigraphy. In this quarterly report, we summarize the progress over the first two quarters of the program for FY93, and project the possible findings during the remainder of the project.