Theoretical response of a seismograph at Yellowknife, Northwest Territories, to an underground explosion at the Nevada test site

1969 ◽  
Vol 6 (3) ◽  
pp. 517-520 ◽  
Author(s):  
H. S. Hasegawa ◽  
K. Whitham
Keyword(s):  
Northwest Territories ◽  
Vertical Component ◽  
Test Site ◽  
Underground Explosion ◽  
Nevada Test Site ◽  
Short Period

A comparison of the theoretical response of the short-period, vertical-component seismograph at Yellowknife to an underground explosion originating at the Nevada Test Site with a real seismogram indicates that the prime contributors to complexity are likely due to the following: (a) complex crustal reverberations at the N.T.S., (b) different phase arrivals, and (c) signal-generated noise at Yellow knife.

Lg magnitudes and yield estimates for underground Novaya Zemlya nuclear explosions

1988 ◽  
Vol 78 (2) ◽  
pp. 873-884
Author(s):  
Otto W. Nuttli
Keyword(s):  
Large Range ◽  
Test Site ◽  
Nevada Test Site ◽  
P Values ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Novaya Zemlya ◽  
Short Period ◽  
Lg Wave ◽  
Range Of Values

Abstract Lg-wave amplitudes of 30 Novaya Zemlya underground nuclear explosions, as recorded by short-period seismographs in Denmark, Finland, Germany, Norway, Spitsbergen, and Sweden, are used to determine mb(Lg) values. Assuming that the mb(Lg) versus explosion yield relation derived from Nevada Test Site data applies to all continental areas, the yields of the explosions are estimated. They cover a large range of values, from 2.5 to 4900 kt. The largest explosion since April 1976 had an estimated yield of 145 kt. The mb(Lg) values, when subtracted from the mb(P) values, can be used to estimate the mb(P) bias between two test sites. In this way, the mb(P) bias between Novaya Zemlya and the Nevada Test Site is estimated to be 0.20 magnitude units.

A discrimination analysis of short-period regional seismic data recorded at Tonto Forest Observatory

1982 ◽  
Vol 72 (4) ◽  
pp. 1351-1366
Author(s):  
J. R. Murphy ◽  
T. J. Bennett
Keyword(s):  
Epicentral Distance ◽  
Test Site ◽  
P Wave ◽  
Set Cover ◽  
Spectral Amplitude ◽  
Nevada Test Site ◽  
Data Set ◽  
Short Period ◽  
Single Station ◽  
Regional Phases

abstract A new seismic discriminant based on spectral differences of regional phases from earthquakes and explosions recorded at a single station has been tested and found to work remarkably well. The test data consisted of a well-constrained set of 30 Nevada Test Site (NTS) explosions and 21 earthquakes located within about 100 km of NTS which were recorded on short-period seismographs at the Tonto Forest Observatory in central Arizona at an epicentral distance averaging 530 km. The events in the data set cover a magnitude range from 3.3 to 4.8 (mb) for which Pn, Pg, and Lg phases have been analyzed. We found that, although Lg phases from earthquakes are typically more prominent than for explosions with comparable P-wave amplitude levels, simple time-domain Lg/P amplitude ratios do not result in a separation of the earthquake and explosion samples consistent enough to provide reliable discrimination. However, spectral analyses of the data over the frequency band from 0.5 to 5.0 Hz revealed significant differences in the spectra of certain regional phases which proved to be a quite reliable discriminant. In particular, both the Pg and Lg spectra from earthquakes have been found to be richer in high-frequency content than corresponding explosion spectra. A discriminant measure, defined as the ratio of average Lg spectral amplitude level in the 0.5- to 1.0-Hz passband to that in the 2.0- to 4.0-Hz passband, provides good separation of earthquake and explosion populations.

Seismic magnitudes of high-yield underground explosions

1970 ◽  
Vol 7 (2) ◽  
pp. 531-534 ◽  
Author(s):  
P. W. Basham
Keyword(s):  
Site Effect ◽  
Test Site ◽  
Aleutian Islands ◽  
High Yield ◽  
Underground Explosion ◽  
Nevada Test Site ◽  
Seismic Magnitude ◽  
Similar Yield

The seismic magnitude of the October 2, 1969 high-yield underground explosion (Milrow) in the Aleutian Islands, when compared to the magnitude of the smaller 1965 Long Shot explosion, suggests that in the yield range near 1 megaton the yield exponent in the amplitude-yield relationship is significantly less than the value of unity which applies for yields less than 100 kilotons. The lower exponent is shown to apply equally well to Nevada Test Site high-yield explosions. A general Aleutian site effect is observed to produce seismic magnitudes for Aleutian explosions that are about m0.3 larger than those of similar-yield explosions at the Nevada Test Site.

Seismic magnitudes of underground nuclear explosions

1973 ◽  
Vol 63 (1) ◽  
pp. 105-131 ◽  
Author(s):  
P. W. Basham ◽  
R. B. Horner
Keyword(s):  
Computational Procedure ◽  
Test Site ◽  
P Wave ◽  
Nevada Test Site ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Novaya Zemlya ◽  
Yield Information ◽  
Short Period ◽  
Propagation Effects

abstract Using an Ms computational procedure that minimizes path-propagation effects, and with Ms values found to be empirically independent of test site and detonation medium among consolidated rock explosions, available yield information is employed to illustrate that the seismic scaling of explosions in realistic detonation environments produces teleseismic Rayleigh-wave displacements proportional to the 1.2-power of yield over the range from low yields to greater than three megatons. Ms values independent of network, path, and site can be employed to estimate unknown yields at uncalibrated test sites to within average errors judged to be about 20 per cent. P-wave magnitudes, in the form of a calibrated teleseismic measure of short-period P-wave displacements, show a theoretically supported dependence of displacement on the 1.1-power of yield over the range from 6 kt to 1 mt. Studied explosions separate into two categories: the Nevada Test Site granite explosions, LONG SHOT, the Sahara February 1965 explosion and (by empirical inference) Novaya Zemlya and Eastern Kazakh explosions exhibit P-wave displacements about a factor of 3 greater than explosions of the same yield in tuff, rhyolite, and shale. P-wave magnitudes of explosions are subject to such a diversity of source, propagation, and measurement phenomena that any estimation of unknown yields without a closely controlled site and network calibration can be subject to large errors.

Travel times and amplitudes of principal body phases recorded from gnome

1962 ◽  
Vol 52 (5) ◽  
pp. 1057-1074 ◽  
Author(s):  
Carl Romney ◽  
Billy G. Brooks ◽  
Robert H. Mansfield ◽  
Dean S. Carder ◽  
James N. Jordan ◽  
...  
Keyword(s):  
United States ◽  
Seismic Waves ◽  
Test Site ◽  
The United States ◽  
Body Waves ◽  
Travel Times ◽  
Eastern United States ◽  
Nevada Test Site ◽  
Short Period ◽  
The Difference

abstract gnome, an undergound nuclear explosion in salt near Carlsbad, New Mexico, produced seismic waves which were recorded widely throughout the United States and at a few foreign stations. The travel times of P were strongly dependent on the path of propagation, and were as much as 12 seconds earlier in the eastern United States than at equivalent distances in the western part of the United States. At the few stations more distant than 25°, P was about 2 seconds earlier than predicted by the Jeffreys-Bullen table for surface focus. Amplitudes of Pn were similarly dependent upon the path of propagation; although the measurements showed great scatter, amplitudes to the east were generally larger than those to the west. Pn travel time and amplitude anomalies suggest a systematic relationship to crustal thickness. There is evidence from the difference in the speeds and attenuation rates that Lg and P are not transmitted along analogous paths through the crust. Short period body waves were two or three times larger than expected from an explosion of the same energy in tuff at the Nevada Test Site. Surface waves, however, were relatively weak compared with explosions of similar yield in tuff.

Properties of Oak Spring formation in Area 12 at the Nevada Test Site

1959 ◽  
Author(s):  
W.H. Diment ◽  
R.E. Wilcox ◽  
G.V. Keller ◽  
E. Dobrovolny ◽  
F.C. Kracek ◽  
...  
Keyword(s):  
Test Site ◽  
Nevada Test Site
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