Technical Report for the Period 1 October-31 December 1986.
Abstract
Work on network design and capability assessment has focused on defining the seismological criteria for selecting stations of a globas seismic network to achieve a specified minimum verification capability. The design criteria are defined with a view toward minimizing the gap between seismic detection threshold and the threshold for recording seismic waves used for discriminating earthquakes from. Research to improve analysis of regional seismic data is currently focused on determining various waveform signatures of events that occur frequently at the same location. Examples being studied include repeated explosions at mines in the western USSR and Scandinavia, presumed underwater detonations off the coast of Norway, and northern European earthquake sequences. Procedures being tested as seismic signature elements include the formation of particle-motion parameters from the six terms of the three-component covariance matrix, plus spectral, cepstral and autoregressive analyses. A review of evidence for high-quality propagation of seismic waves at regional distance ranges in the USSR was conducted. The available data are consistent with maximum Q sub a of about 2,000 for regional seismic waves. In both the Baltic shield and central Asia, high-frequency signals from small events are observed to about 500-600 km, but disappear into the noise at larger distance ranges. Keywords: Primary waves(Seismic waves); Polarization; Nuclear explosion monitoring; Seismic attenuation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1987
- Accession Number
- ADA179377
Entities
Organizations
- Leidos