AN ANALYSIS OF LONGSHOT DATA FOR THE CANADIAN SEISMIC STATIONS.
Abstract
A pilot analysis of the Long Shot nuclear explosion data received by the Canadian seismic stations indicates a consistent compressional first arrival as expected from an impulsive explosion source. Significant travel time discrepancies are observed in the commencement of the P arrival which arrived up to 6 seconds early at all stations with the largest residuals at the most distant sites. A comparison earthquake in the Rat Islands area indicates a similar bias trend. The P arrival amplitudes appear to be anomalously low in the central B.C. area and high in eastern Canada. The effect is also evident in the magnitude determinatuions which are based on these amplitudes. The causes of the variations of magnitudes and the anomalously low amplitudes have not been explained. The average magnitude and standard deviation for all Canadian stations is shown to be 6.01 plus or minus 0.40 which agrees well with the world wide average determination of 5.99 plus or minus 0.52. Spectral investigations demonstrate that there are both common and individual characteristics among the ground amplitude spectra of the different stations. These characteristics have not been correlated to the explosion source mechanism or to geological structure although some causative suggestions have been made. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1966
- Accession Number
- AD0638752
Entities
People
- Oliver George Jensen