Analysis of an Eastern Kazakh explosion using regional Chinese seismograms: a pilot study

Technical Report · Thu Aug 19 04:00:00 EDT 1982

OSTI ID:6817702

Harris, D B; Taylor, S R; Patton, H J

A preliminary study of broadband regional seismic signals from an Eastern Kazakh explosion recorded at the Urumchi station in western China was made to evaluate data quality and to examine the feasibility of additional source and structural investigations. The data consist of broadband (flat to displacement between 0.08 and 10 Hz), photographic records from an SK Kirnos galvanometric system. The vertical-component seismogram appears similar to that expected for an eastern US path with the exception of the surface wave train which exhibits strong dispersion, especially for periods less than 7. Simultaneous inversion of Rayleigh wave phase and group velocities yield a crustal model dominated by the presence of very low velocities and a strong positive velocity gradient above 15 km depth. Velocities below 15 km depth are not significantly different from other continental structures underlain by Paleozoic or Precambrian basement. This model is consistent with geologic considerations indicating that most of the path is characterized by the presence of up to 10 km of sediments overlying a Paleozoic basement. The seismic moment of this event was measured using the Rayleigh-wave spectrum in the band 0.05 to 0.2 Hz. Assuming a spherically symmetric source and an amplitude decay rate similar to the eastern US, we obtain a moment of 2.5 x 10/sup 23/ dyn-cm for an explosion with a modest overshoot (B=2) in hard rock and a moment of 1.0 x 10/sup 23/ dyn-cm with a large overshoot (B=10). Using an estimate of the seismic moment and empirical relationships between moment and yield for NTS explosions, we can infer the yield. Uncertainties in the moment and in the moment-yield relationship give rise to an inferred yield ranging from 55 kt to 300 kt. Although this range is unacceptably large, substantial improvements can result with further constraints on the explosion source model and more work on the relationships between moment and yield.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6817702
• Report Number(s): UCID-19503; ON: DE82022514
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
450200 -- Military Technology
Weaponry
& National Defense-- Nuclear Explosions & Explosives
450300* -- Military Technology
Weaponry
& National Defense-- Nuclear Explosion Detection
ASIA
CHINA
DATA ANALYSIS
DETECTION
EXPLOSIONS
NUCLEAR EXPLOSION DETECTION
NUCLEAR EXPLOSIONS
SEISMIC DETECTION
UNDERGROUND EXPLOSIONS