Sourcebook of Locations of Geophysical Surveys in Tunnels and Horizontal Holes Including Results of Seismic-Refraction Surveys: Rainier Mesa, Aqueduct Mesa, and Area 16, Nevada Test Site

摘要

Seismic refraction surveys have been obtained sporadically in tunnels in zeolitized tuff at the Nevada Test Site since the late 1950's. Commencing in 1967 and continuing to date (1982), extensive measurements of shear- and compressional-wave velocities have been made in five tunnel complexes in Rainier and Aqueduct Mesas and in one tunnel complex in Shoshone Mountain. The results of these surveys to 1980 are compiled in this report. In addition, extensive horizontal drilling was initiated in 1967 in connection with geologic exploration in these tunnel complexes for sites for nuclear weapons tests. Seismic and electrical surveys were conducted in the majority of these holes. The type and location of these tunnel and borehole surveys are indexed in this report. Synthesis of the seismic refraction data indicates a mean compressional-wave velocity near the nuclear device point (WP) of 23 tunnel events of 2430 m/s (7970 f/s) with a range of 1846 to 2753 m/s (6060 to 9030 f/s). The mean shear-wave velocity of 17 tunnel events is 1276 m/s (4190 f/s) with a range of 1140 to 1392 m/s (3740 to 4570 f/s). Experience indicates that these velocity variations are due chiefly to the extent of fracturing and (or) the presence of partially saturated rock in the region of the survey. (ERA citation 08:050094)