Attenuation of seismic waves at regional distances. Final technical report, 1 October 1982-30 September 1984
The coda-Q method was applied to determine the anelastic attenuation of 1-sec period Lg waves at NTS(Nevada Test Site), East Kazakh, the Indian subcontinent, and the South American continent. Mb(Lg) m sub b (Lg) versus explosion yield calibration curves are given for NTS explosions in hard rock and in alluvium. The NTS hard-rock calibration curve, when applied to explosions in other regions of the United States and in the French Sahara, gives realistic yield estimates. The technique also is applied to selected Soviet explosions in East Kazakh. M sub b (Lg) and M sub b (P) values were used to estimate the M sub b (P) bias between NTS and eastern North America. Assuming that explosions and earthquakes of the same M sub b (P) value excite Lg waves of equal amplitude, the P-wave magnitude bias between NTS and eastern North America. Assuming that explosions and earthquakes of the same M sub b (P) value excite Lg waves of equal amplitude, the P-wave magnitude bias between NTS and eastern North America is 0.31 magnitude units. A tentative value for the bias between NTS and Shagan River is 0.41 magnitude units, but this value may be changed. Frequency-dependence of crustal Q seems significant in regions of high Q, but are small or non-existent in regions of low Q values.
- Research Organization:
- Saint Louis Univ., MO (USA). Dept. of Earth and Atmospheric Sciences
- OSTI ID:
- 5754173
- Report Number(s):
- AD-A-150198/0/XAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
450300* -- Military Technology
Weaponry
& National Defense-- Nuclear Explosion Detection
58 GEOSCIENCES
580201 -- Geophysics-- Seismology & Tectonics-- (1980-1989)
ASIA
ATTENUATION
CALIBRATION
EARTHQUAKES
EASTERN EUROPE
ENERGY-LEVEL TRANSITIONS
EUROPE
EXCITATION
EXPLOSIONS
HARDNESS
LATIN AMERICA
MECHANICAL PROPERTIES
NORTH AMERICA
NUCLEAR EXPLOSIONS
SEISMIC EVENTS
SEISMIC WAVES
SOUTH AMERICA
USSR