scholarly journals Surface-wave generation by underground nuclear explosions releasing tectonic strain

1980 ◽  
Author(s):  
H.J. Patton
Keyword(s):  
Surface Wave ◽  
Wave Generation ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions

scholarly journals Vertical force scaling in seismic source models of underground nuclear explosions

2020 ◽  
Vol 221 (1) ◽  
pp. 251-264
Author(s):  
Michael Howe ◽  
Göran Ekström ◽  
Paul G Richards
Keyword(s):  
Surface Wave ◽  
Body Wave ◽  
Scaling Factor ◽  
Body Waves ◽  
Burial Depth ◽  
Vertical Force ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Seismic Source Models ◽  
Force Scaling

SUMMARY We have reanalysed observations of body waves and surface waves for 71 well-recorded underground nuclear explosions (UNEs) that were conducted between 1977 and 1989 at the Balapan subregion of the Semipalatinsk Test Site in Kazakhstan. To reconcile differences between body-wave and surface-wave amplitudes, we solve for a scaling factor between vertical and horizontal forces in the explosion model. We find that the estimated scaling factor is anticorrelated with the scaled depth of burial for the subset of UNEs at Balapan that have published depths. The observed anticorrelation and the inferred variations in force scaling suggest that recorded surface-wave amplitudes are significantly influenced by UNE burial depth as well as by previously recognized tectonic release. As part of our analysis, we revisit the relationship between teleseismic mb(P) and yield for UNEs at Balapan, and discuss the physical basis for effectiveness of the mb–MS discriminant.

S waves generated by small seismic sources

1966 ◽  
Vol 290 (1422) ◽  
pp. 448-460
Keyword(s):  
Wave Motion ◽  
Wave Generation ◽  
Good Resolution ◽  
University Of Michigan ◽  
Period Range ◽  
S Waves ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Wide Range ◽  
The University

Observations of S waves from small earthquakes recorded at near distances indicate that the relative S wave generation extends over a wide range. Similar measurements from underground nuclear explosions indicate a ratio of S to P wave generation to be below the observed values for 70 % of the earthquakes studied. The observation of S waves from small events at teleseismic distances is made difficult by interference of microseisms in the period range where S waves may be expected. The observation is also made difficult by the physical requirement that two horizontal component seismographs are required to obtain good resolution of S wave motion. Some measurements have been made at the University of Michigan by means of three-component seismometers in arrays to obtain better resolution of S wave motion. The results of these measurements suggest that improvements in S wave signal/noise ratios similar to those obtained for P waves are possible. The use of S waves from small events at teleseismic distances should not be considered of value as a method of detection. It does, however, offer promise as an added method of identification for small seismic events.

Short-period seismic energy radiation patterns from underground nuclear explosions and small-magnitude earthquakes

1967 ◽  
Vol 57 (2) ◽  
pp. 249-267 ◽  
Author(s):  
George H. Sutton ◽  
Walter Mitronovas ◽  
Paul W. Pomeroy
Keyword(s):  
United States ◽  
Surface Wave ◽  
Total Energy ◽  
Seismic Energy ◽  
The United States ◽  
Radiation Patterns ◽  
Small Magnitude ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Short Period

abstract Azimuthal radiation patterns of short-period (0.5-2.0 cps) seismic energy obtained from integrals of the seismograms from two underground nuclear explosions and two earthquakes are used to study the propagation and source characteristics of the Pg and Lg phases in the United States. In addition, the energy spectrum is divided into two bands, greater than and less than 1.4 cps, and the ratio of higher-to-lower-frequency energy is mapped to study the nature of propagation as a function of frequency. Both the total energy and the ratio show large fluctuations with azimuth and distance. However, a general correlation is found between the energy and ratio contours and the major tectonic provinces of the United States. This correlation is attributed to focusing, resulting from lateral variations in velocity and to regional differences in attenuation of the seismic energy. The range in the Q values across the United States, based on the assumption of symmetrical surface wave propagation, is from 200 to 1000, about a factor of 5. The transverse (T) component shows about the same total energy and ratio contour patterns as the vertical (Z) and longitudinal (L) components. Also, energy contour maps are similar to maps obtained using the maximum amplitudes of the Pg and Lg phases. For the events examined, it seems that the nature and distribution of tectonic features along the propagation path are more important in detemining the resultant radiation patterns than the initial conditions at the source. The particle motion at most stations does not give direct proof for the surface wave nature of the Pg and Lg phases, except that Pg tends to be longitudinal or mixed and Lg transverse or mixed.

scholarly journals Discriminating underground nuclear explosions leading to late-time radionuclide gas seeps

2020 ◽  
Author(s):  
Dylan Robert Harp ◽  
Suzanne Michelle Bourret ◽  
Philip H. Stauffer ◽  
Ed Michael Kwicklis
Keyword(s):  
Late Time ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Gas Seeps
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