Seismic source function for an underground nuclear explosion

Journal Article · Fri Feb 01 04:00:00 EDT 1974 · Bull. Seismol. Soc. Amer., v. 64, no. 1, pp. 131-148

DOI:https://doi.org/10.1016/0148-9062(74)91163-2· OSTI ID:4333101

Aki, K; Bouchon, M; Reasenberg, P

The reduced displacement potential obtained from close-in observation of seismic displacement during an underground explosion usually takes the forM of a step function with or without a small overshoot. Theoretical prediction by shockwave calculation appears to agree with the close-in data. The step-function source has also been supported by the observations on Rayleigh waves at periods longer than 10 sec. Some inconsistency between the published data on residual potentials obtained from close-in data and those on seismic moments obtained from long-period Rayleigh waves were found. It appears that only about 1/3 of the residual potential is transmitted to the far-field at long periods. This discrepancy is, however, consistent with several observations made on teleseismic signals suggesting an impulse rather than a step as the primary form of the potential function. New observations of the two NTS events at distances 2.6 to 7.8 km using wide dynamic range, wide-band accelerometers, combined with data from the far-field, support a large overshoot 4 to 5 times the residual value. This result accounts for the efficiency of the M/sub s/-m/sub b/ discriminant between earthquakes and explosions with m/sub b/ around 4 and greater. The compaction of the source volume by spalling was suggested as a possible mechanism for the large overshoot. (auth)

• Research Organization: Massachusetts Inst. of Tech., Cambridge
• Sponsoring Organization: USDOE
• NSA Number: NSA-29-024160
• OSTI ID: 4333101
• Journal Information: Bull. Seismol. Soc. Amer., v. 64, no. 1, pp. 131-148, Journal Name: Bull. Seismol. Soc. Amer., v. 64, no. 1, pp. 131-148; ISSN BSSAA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*EARTHQUAKES-- SEISMIC DETECTION
*NUCLEAR EXPLOSION DETECTION-- SEISMIC WAVES
*NUCLEAR EXPLOSIONS-- SEISMIC DETECTION
N42510* --Engineering--Nuclear Explosions--Detection Systems
UNDERGROUND EXPLOSIONS NUCLEAR EXPLOSION DETECTION