Yield Estimation of Novaya Zemlya Explosions from Short-Period Body Waves

• Main Authors: Chan, W. W., McLaughlin, K. L., Cessaro, R. K., Marshall, M. E., Lees, A. C.
• Other Authors: TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
• Format: Text
• Language: English
• Published: 1988
• Subjects: Seismic Detection and Detectors; Nuclear Weapons; *YIELD(NUCLEAR EXPLOSIONS); *NUCLEAR EXPLOSIONS; *SEISMIC DETECTION; SPECTROMETRY; DEPTH; PHASE; ESTIMATES; MULTIBURSTS; ANISOTROPY; SEISMIC WAVES; DELAY; CALIBRATION; SPECTRAL ENERGY DISTRIBUTION; AMPLITUDE; AZIMUTH; TIME DOMAIN; PRIMARY WAVES(SEISMIC WAVES); SEISMIC ARRAYS; EXCITATION; NETWORKS; MEASUREMENT; SHORT RANGE(TIME); BODY WAVES(SEISMIC WAVES); Novaya Zemlya
• Online Access: http://www.dtic.mil/docs/citations/ADA203393; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA203393

This study investigates the characteristics of Novaya Zemlya explosions using various body wave phases. This information will be used to calibrate the yields of these explosions. The azimuthal variation of amplitude for the Novaya Zemlya explosions as seen from WWSSN recordings indicates that there is a strong component of near-source heterogeneity due to multiple source excitation, near-source structural heterogeneity, or source anisotropy. The systematic azimuthal variation in amplitude may be modeled with a sin (2 Theta) curve, which allows an estimate of the magnitude bias due to certain network station distributions. Several events that have an azimuthal variation in amplitude which departs from a sin (2 Theta) curve may be possible multiple explosions. Clear pP and pPcP depth phases can be observed in deconvolved teleseismic P-wave and PcP-wave source time functions from Novaya Zemlya events. With few exceptions, pP and pPcP delay times show a systematic increase with increasing size. Relative explosion source size estimates are presented based on spectral measures of P, PcP, and P diff at EKA and WRA arrays. These spectral energy measurements may be correlated with the mb estimates to provide an independent calibration of magnitudes. The time domain measurements of P'P' for Novaya Zemlya recorded on WWSSN stations are used to provide a calibration of the mb estimates from P-waves which are quite often clipped for large events. Using a distance-amplitude correction obtained from the data set, the mb estimates for P'P' are computed using a generalized linear model.