CaltechAUTHORS
  A Caltech Library Service

Evidence of tectonic release from underground nuclear explosions in long-period S waves

Wallace, Terry C. and Helmberger, Donald V. and Engen, Gladys R. (1985) Evidence of tectonic release from underground nuclear explosions in long-period S waves. Bulletin of the Seismological Society of America, 75 (1). pp. 157-174. ISSN 0037-1106. http://resolver.caltech.edu/CaltechAUTHORS:20140812-133439918

[img]
Preview
PDF - Published Version
See Usage Policy.

1164Kb

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20140812-133439918

Abstract

The SH waves from 21 underground nuclear explosions at Pahute Mesa (NTS) were used to investigate tectonic release. The equivalent double-couple representation of the tectonic release, which was constrained by waveform modeling and the polarity of sP, is very similar for all the explosions. The average orientation is a right-lateral, strike-slip fault trending N15°W. Seismic moments were determined on the basis of comparisons with two western United States strike-slip earthquakes. BENHAM has the largest tectonic release moment (5.6 × 10^(24) dyne-cm) and STILTON (0.1 × 10^(24) dyne-cm) the smallest of the events studied. In general, the seismic moments increase with the size of the explosion, but the location of the explosion relative to previous explosions can strongly affect the tectonic release. The Pahute Mesa events can be separated into two populations: (1) events which are well separated (>4 km) from previous explosions, and (2) those events which are close (<4 km) to previous explosions. Those events which are close to previous explosions show a marked decrease in tectonic release. A least-squares fit of seismic moment to event size (as determined from the world wide, average ab amplitude) shows that the two populations are approximately parallel, but offset. The fact that the trends remain separated even at small yields (e.g., PIPKIN and SCOTCH) suggests that for Pahute Mesa there is not a threshold for tectonic release. Since spatial position gives the best separation of high and low tectonic release events, a volume model is favored for the source mechanism. The preferred model is motion on a system of faults and joints.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://bssa.geoscienceworld.org/content/75/1/157.abstractPublisherArticle
Additional Information:© 1985 Seismological Society of America. Manuscript received 11 August 1982. The authors wish to thank Thorne Lay and Larry Burdick for reviewing this manuscript and offering constructive criticism. This research was supported by the Advanced Research Projects Agency of the Department of Defense and was monitored by the Air Force Office of Scientific Research under Contract F49620-81-C-0008.
Funders:
Funding AgencyGrant Number
Advanced Research Projects Agency (ARPA)UNSPECIFIED
Air Force Office of Scientific Research (AFOSR)F49620-81-C-0008
Record Number:CaltechAUTHORS:20140812-133439918
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140812-133439918
Official Citation:Wallace, T. C., Helmberger, D. V., & Engen, G. R. (1985). Evidence of tectonic release from underground nuclear explosions in long-period S waves. Bulletin of the Seismological Society of America, 75(1), 157-174.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48414
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:12 Aug 2014 21:45
Last Modified:12 Aug 2014 21:45

Repository Staff Only: item control page