As part of the Geological Survey's study of the Long Valley area, an attempt was made to define the regional thermal setting of the caldera. The first phase of this study involved the drilling of four holes in granitic rocks outside of the caldera and two holes within it (Figure 1). LV was drilled as a hydrologic test well. In Figure 1, the light areas are areas of crystalline rocks and the stippled area, volcanic and sedimentary rocks. (For an explanation of the symbols, see Plate 1 of Bateman and others (1963).) Preliminary temperature measurements and thermal conductivity determinations have been completed and are presented in this report. Also presented herein are data obtained in November 1973 from the shallow holes drilled by Lewis (1974) and some thermal conductivity values from these short holes. These preliminary data are being released now because of intense public interest. The study is continuing, and an interpretive report will be written later this year. The temperature measurements are presented in both graphs and tables. Thermal conductivity data are tabulated as a function of depth for each hole. For locations of the shallow test wells, reference should be made to the quadrangle maps shown in Figures 3 through 13 of Lewis (1974).
