AEC research reports. WT-1531. Operation, plumbbob, Nevada test site, May-Oct. 1957 [report to test director]; project 26.4e, Subsurface accelerations and strains from an underground detonation, pt. 2 [with list of references]; [by F. A. Pieper, A. C. Tiemann and R. H. Sievers, jr.]