Yield Estimation and Mantle Q
Abstract
Spectral analysis of P waves crossing the mantle under various test sites has revealed considerable variations in the attenuative properties of the mantle which must be considered when computing yields of nuclear explosions. The t* bias between the NTS and Kazakh test sites must be in the range 0.2 to .3 sec. There are indications of anomalous zones of attenuation under the French test sites in the Sahara and near some suspected nuclear explosions in the Baykal area. Mantle attenuation under the Sahara test sites appears to be intermediate between a shield and the western United States. Other test sites for which we have relevant results seem to be in areas of low mantle attenuation. Patterns of attenuation found by analyses of nuclear explosion data fit roughly in the worldwide patterns found in more general studies of plate tectonics. No test sites are located in areas of extremely low Q zones in the mantle, such as those found under some back-arc basins. Empirical analyses and synthetic simulations give the formula: delta m(sub b) = approx. 1.35 delta t*(sub p) for deriving the m(sub b) bias from a t* differential. Regional patterns of lateral Q variations found by spectral analyses are well correlated with several other relevant geophysical parameters, such as P (sub n) velocities, travel time variations of P and S waves, heat flow, and upper mantle conductivity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 29, 1983
- Accession Number
- ADA169613
Entities
People
- Zoltan A. Der