GROUND MOTION MEASUREMENTS. Project 26.3 of OPERATION HARDTACK, PHASE II
None · 1959
Measurements were made of strong ground motion occurring in the medium surrounding the Evans event of Operation Hardtack Phase II. Due to the low yield of the Evans device no usable records were obatined from the event. A preliminary analysis isgiven of measurements of strain and acceleration made on the Tamalpais event in an effort to improve the instrumentation for Evans. A tentative correlation of data on accelerations and strains from contained underground explosions in the Oak Springs tuff indicates that the effectiveness omalpais in causing ground motion was less than 10% of that expected on the basis of cube root scaling from a 1-ton, fully stemmed HE model test. (auth)