| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
SEISMOLOGICAL LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY, PASADENA, CALIFORNIA 91125
Abstract
In this paper, we study the long-period body waves at regional and upper mantle distances from large underground nuclear explosions at Pahute Mesa, Nevada Test Site. A comparison of the seismic records from neighboring explosions shows that the more recent events have much simpler waveforms than those of the earlier events. In fact, many of the early events produced waveforms which are very similar to those produced by shallow, moderate-size, strike-slip earthquakes; the phase sP is particularly obvious. The waveforms of these explosions can be modeled by assuming that the explosion is accompanied by tectonic release represented by a double couple. A clear example of this phenomenon is provided by a comparison of GREELEY (1966) and KASSERI (1975). These events are of similar yields and were detonated within 2 km of each other. The GREELEY records can be matched by simply adding synthetic waveforms appropriate for a shallow strike-slip earthquake to the KASSERI observations. The tectonic release for GREELEY has a moment of 5 x 1024 dyne-cm and is striking approximately 340°. The identification of the sP phase at upper mantle distances indicates that the source depth is 4 km or less. The tectonic release time function has a short duration (less than 1 sec). A comparison of these results with well-studied strike-slip earthquakes on the west coast and eastern Nevada indicate that, if tectonic release is triggered fault motion, then the tectonic release is relatively high stress drop, on the order of several hundred bars. It is possible to reduce these stress drops by a factor of 2 if the tectonic release is a driven fault; i.e., rupturing with the P velocity. The region in which the stress is released for a megaton event has a radius of about 4 km. Pahute Mesa events which are detonated within this radius of a previous explosion have a substantially reduced tectonic release.
This article has been cited by other articles:
|
|
 |
|
  Scattering from Tunnels near Sources and their Effect on Seismic Signatures of Explosions Bulletin of the Seismological Society of America, February 1, 2000; 90(1): 229 - 242.
|
|
|
|
|
|
J. Zhang Source characterization using simplified waveforms: Tests on earthquakes and nuclear explosions in Xinjiang, China Bulletin of the Seismological Society of America, August 1, 1997; 87(4): 832 - 846. [Abstract] [PDF]
|
|
|
|
|
|
R. L. Gibson Jr., M. N. Toksoz, and W. Dong Seismic radiation from explosively loaded cavities in isotropic and transversely isotropic media Bulletin of the Seismological Society of America, December 1, 1996; 86(6): 1910 - 1924. [Abstract] [PDF]
|
|
|
|
|
|
H. J. Patton and S. R. Taylor Analysis of Lg spectral ratios from NTS explosions: Implications for the source mechanisms of spall and the generation of Lg waves Bulletin of the Seismological Society of America, February 1, 1995; 85(1): 220 - 236. [Abstract] [PDF]
|
|
|
|
|
|
S. C. Harmsen The Little Skull Mountain, Nevada, earthquake of 29 June 1992: Aftershock focal mechanisms and tectonic stress field implications Bulletin of the Seismological Society of America, October 1, 1994; 84(5): 1484 - 1505. [Abstract] [PDF]
|
|
|
|
|
|
H. J. PATTON Source models of the Harzer explosion from regional observations of fundamental-mode and higher mode surface waves Bulletin of the Seismological Society of America, June 1, 1988; 78(3): 1133 - 1157. [Abstract] [PDF]
|
|
|
|
|
|
B. P. COHEE and T. LAY Modeling teleseismic SV waves from underground explosions with tectonic release: Results for Southern Novaya Zemlya Bulletin of the Seismological Society of America, June 1, 1988; 78(3): 1158 - 1178. [Abstract] [PDF]
|
|
|
|
|
|
A. DOUGLAS and D. W. RIVERS An explosion that looks like an earthquake Bulletin of the Seismological Society of America, April 1, 1988; 78(2): 1011 - 1019. [PDF]
|
|
|
|
|
|
V. F. CORMIER Focusing and defocusing of teleseismic P waves by known three-dimensional structure beneath pahute mesa, Nevada Test Site Bulletin of the Seismological Society of America, October 1, 1987; 77(5): 1688 - 1703. [Abstract] [PDF]
|
|
|
|
|
|
R. W. BURGER, T. LAY, T. C. WALLACE, and L. J. BURDICK Evidence of tectonic release in long-period S waves from underground nuclear explosions at the Novaya Zemlya test sites Bulletin of the Seismological Society of America, June 1, 1986; 76(3): 733 - 755. [Abstract] [PDF]
|
|
|
|
|
|
A. DOUGLAS, J. B. YOUNG, and N. S. LYMAN Comments on a paper and a reply to a note by T. C. Wallace, D. V. Helmberger, and T. Lay Bulletin of the Seismological Society of America, February 1, 1986; 76(1): 305 - 311. [PDF]
|
|
|
|
|
|
T. C. WALLACE, D. V. HELMBERGER, and T. LAY Reply to comments by A. Douglas, J. B. Young, and N. S. Lyman and a note on the revised moments for Pahute Mesa tectonic release Bulletin of the Seismological Society of America, February 1, 1986; 76(1): 313 - 318. [PDF]
|
|
|
|
|
|
P. SCOTT and D. V. HELMBERGER Applications of the transmitted Kirchhoff-Holmholtz method to transmitted body waves and possible structural effects at NTS Bulletin of the Seismological Society of America, February 1, 1985; 75(1): 131 - 156. [Abstract] [PDF]
|
|
|
|
|
|
T. LAY, T. C. WALLACE, and D. V. HELMBERGER The effects of tectonic release on short-period P waves from NTS explosions Bulletin of the Seismological Society of America, June 1, 1984; 74(3): 819 - 842. [Abstract] [PDF]
|
|
|
|
|
|
T. LAY, D. V. HELMBERGER, and D. G. HARKRIDER Source models and yield-scaling relations for underground nuclear explosions at Amchitka Island Bulletin of the Seismological Society of America, June 1, 1984; 74(3): 843 - 862. [Abstract] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
