Finite Difference Cratering Support. Analysis of Regional Data from Cratering and Non-Cratering Nuclear Explosions
Abstract
A comparison of regional phases generated by contained and cratering nuclear explosions is made by examining the amplitudes of various phases and by spectral analyses. Using Ringdal's maximum likelihood method, in which one can also make use of clipped readings as well as noise measurements, amplitudes of the regional phases Pn, Pg, Lg (corrected for spatial attenuation) and the ratio Pmax/Pa (where Pmax is the largest amplitude in the first 5 sec of Pn and where Pa refers to the a phase) were plotted against the known yields of explosions. No systematic distinction could be observed, at regional distances, between cratering and noncratering explosions at Nevada Test Site; the excitation of various regional phases appears to depend more on conditions at or near the source than on whether the shot produced a crater or not. We also examined the spectra of Pn on KN-UT records of several Pahute Mesa explosions covering a wide range of scaled depths. The observed modulation of Pn spectra agreed with that expected due to cancellation by pP in only a few instances. A comparison of the Pn spectra of closely spaced explosions suggested that the pP arrivals are probably severely distorted by the effects of inelastic processes in the source region of large explosions and scattering due to large lateral variations. These two effects may, in most cases, be strong enough not only to obliterate any definite evidence of the classical pP arrival but also mask any differences between cratering and contained explosions recorded at regional distances.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1988
- Accession Number
- ADA194496
Entities
People
- I. N. Gupta
- K. L. Mclaughlin
- R. W. Wagner
Organizations
- Teledyne Technologies