Compilation of results of three-dimensional stress determinations made in Rainier and Aqueduct Mesas, Nevada Test Site, Nevada

Since 1971, the US Bureau of Mines overcore method has been used to determine the state of stress at nine locations within Rainier and Aqueduct Mesas at the Nevada Test Site, Nevada. Results of these determinations indicate a generally consistent pattern of relatively high stress in a northeast-southwest direction and relatively low stress in a northwest-southeast direction within the mesas. The pattern is consistent with estimates of the regional stress orientation based on geologic and geophysical evidence, including earthquake focal-plane solutions. The state of stress in Rainier and Aqueduct Mesas is probably mostly tectonic in origin, with significant modifications in stress magnitude and orientation owing to the topography of the mesas, their location above the average regional elevation, and influence of local geologic features at individual measurement locations