Regional m/sub b/:M/sub s/ discrimination of NTS explosions and western United States earthquakes. Progress report
The m/sub b/:M/sub s/ discriminant is evaluated in the western US (WUS) using 330 NTS explosions and 130 WUS earthquakes in the magnitude range of 2.5 to 6.5. The data were recorded at four broadband seismic stations operated by Lawrence Livermore National Laboratory (LLNL) surrounding NTS at distances of about 200 to 400 km. The propagation paths for the earthquakes range from approximately 175 to 1300 km and are confined mainly to the Basin and Range. A linear discrimination analysis indicates significant variability in m/sub b/:M/sub s/ performance between the four stations ranging from approximately 6% probability of misclassification (ELK) to 19% (LAC). This range of performance is surprisingly large and suggests that effects of receiver structure on regional discrimination are significant. Relative to other discriminants tested as part of this study, the m/sub b/:M/sub s/ discriminant appears to work fairly well at regional distances in the Basin and Range for m/sub b/ greater than or equal to 4.0 to 4.5 (corresponding to tamped explosion yields in hard rock of approximately 3 to 10 KT). The earthquake measurements showed greater variability than the explosions and the probability of misclassifying an earthquake was generally 6 to 11% greater than the probability of misclassifying an explosion. This is probably due to the wider range of travel paths, focal mechanisms, and depths sampled by the earthquake population. A major disadvantage of the m/sub b/:M/sub s/ technique is the difficulty in obtaining long-period Rayleigh-wave measurements below m/sub b/ approx.4 for explosions. However, this fact may be useful in identifying events at small magnitudes using negative evidence. 41 refs., 8 figs., 3 tabs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6295964
- Report Number(s):
- UCID-20642; ON: DE86005763
- Country of Publication:
- United States
- Language:
- English
Similar Records
Discrimination between NTS explosions, earthquakes and the non-proliferation experiment at the Pinedale Seismic Research Facility
Detection of long-period S from earthquakes and explosions at LASA and LRSM stations with application to positive and negative discrimination of earthquakes and underground explosions. Technical report
Related Subjects
450300* -- Military Technology
Weaponry
& National Defense-- Nuclear Explosion Detection
DETECTION
EARTHQUAKES
EVALUATION
EXPLOSIONS
FEDERAL REGION IX
NORTH AMERICA
RAYLEIGH WAVES
SEISMIC DETECTION
SEISMIC EVENTS
SEISMIC S WAVES
SEISMIC SURFACE WAVES
SEISMIC WAVES
UNDERGROUND EXPLOSIONS
USA