CRATER STABILITY UNDER THE INFLUENCE OF LARGE SEISMIC MOTIONS

摘要

This report is an empirical study of the effects of large seismic motions on crater slopes. Data were obtained from measure ments of the effects of the seismic motions generated by the Handley Event on the Cabriolet and Schooner craters. Accelerometers recorded the ground motions;aerial photographs and ground surveys documented the permanent ground displacements.nThe Handley Event was detonated on Pahute Mesa at the Nevada Test Site approximately 10,000 ft from the Cabriolet 'charter and 18,000 ft from the Schooner crater. The slopes at Cabriolet were subjected to the estimated peak radial (horizontal) accelera¬tion of 0.74 g;the slopes at Schooner, to 0.36 g. .nMaterial displacements at Cabriolet and Schooner craters were confined to the loose surface material and individual boulders. Visible downslope movement occurred in the fallback, and tension cracks appeared in the apparent crater lips, but no adjustments in the true crater were observed. Since no major changes in crater geometry occurred under severe ground acceleration, it appears that crater slopes are likely to remain essentially stable when subjected to large seismic motions.