New Techniques for Estimating Source Depth and Other Diagnostic Source Characteristics of Shallow Events from Regional Observations of P, Lg, and Rg Signals,
Abstract
As part of a broader study to develop effective regional discriminants for Iran (and other areas of interest) a new cepstral stacking method for estimating source depth from a single, short-period regional station has been developed and tested, and new insights have been gained on why high frequency Lg/P is a very good discriminant for different source regions while low-frequency (less than about 5 Hz) Lg/P is not. It is shown that stacking (product or sum) of the cepstra of multiple sub-windows spanning the total P and P-coda time window enhances the depth phase delays, (pP - P) and (sP - P), with respect to other delay times from crnstal phases, such that accurate depth determination can be made from a single, short-period regional signal. Further enhancement can be achieved by also stacking individual stacked cepstra over multiple regional stations. The stacked product of individual cepstra gives a better result than the stacked sum, because contributions from other delay times that are prominent in some sub-windows are more-effectively suppressed in the product. The method has been tested on regional events in fran for which multiple teleseismic pP observations are available; on Soviet Test Site (STS) nuclear explosions and one STS earthquake recorded in Iran; and on synthetic regional signals. It appears that with reasonable signal bandwidth and signal-to-noise levels accuracies in depth of about 1 km or better can be achieved for crustal events using this method.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 14, 1995
- Accession Number
- ADP204501
Entities
People
- David H. Salzbert
- Indra N. Gupta
- Roy C. Hsu
- Shelton S. Alexander
- Sheri L. Karl
Organizations
- Pennsylvania State University