Rapid Reconnaissance of Geothermal Prospects Using Shallow Temperature Surveys. Semi-Annual Technical Report

摘要

Shallow (2-m) soil temperature data have been collected at 27 sites at Long Valley, California and at 102 sites at Coso, California. These geothermal areas are locations where traditional deep reconnaissance geothermal survey bore holes have been emplaced, allowing us to compare directly the shallow temperature results with standard geothermal exploration techniques. The effects of surface roughness, albedo, soil thermal diffusivity, topography and elevation in making the necessary corrections to the 2-m temperature data were considered. The corrected data for both locations have been plotted up by computer to avoid any personal bias, and have been compared with the published 10-m contour data at Long Valley and the 30-m contour data for Coso. Close geometrical similarity has been observed. Additionally, previously located faults have been identified with the shallow temperature survey technique. Due to the relative inexpensiveness of the technique, it was concluded that shallow temperature exploration should be one of the first geophysical surveys initiated at a geothermal prospect to help guide the development and expenditure of financial resources when embarking on a detailed exploration program.