Accession Number:

ADA516373

Title:

Discrimination Calibration Analysis Methods for Regional Stations

Descriptive Note:

Conference paper

Corporate Author:

PACIFIC NORTHWEST NATIONAL LAB RICHLAND WA

Personal Author(s):

• Anderson, Dale N.
• Fagan, Deborah K.
• Taylor, Steven R.
• Mercier, Theresa M.

Report Date:

2008-09-01

Pagination or Media Count:

10.0

Abstract:

For event discrimination, operational implementation of a regional seismic station requires three sequential calibration analyses. 1 Magnitude, distance, and amplitude corrections MDAC made to observe regional amplitudes are necessary so that what remains in the corrected amplitude is mostly information about the seismic source-type. Corrected amplitudes can be used in ratios to discriminate between earthquakes and explosions. Calibration of MDAC can be accomplished with empirical Bayes estimation, which naturally provides metrics to determine when adequate calibration data have been acquired, and provides statistical assurance that the errors associated with MDAC calibration are negligible in future operational discrimination analysis. 2 MDAC-corrected amplitudes can then be used in ratios to discriminate between earthquakes and explosions. However, there remain source effects such as those due to depth, focal mechanism, local material property and apparent stress variability that cannot easily be determined and applied as amplitude corrections. We have developed a mathematical model to capture these near source effects as random unknown giving an error partition of three sources model inadequacy, station noise and amplitude correlation. This mathematical model is the basis for a general multi-station regional discriminant. Calibration analysis for the standard error of the discriminant includes the calculation of the variances of model inadequacy and station noise, and amplitude correlation. 3 Likelihood-based seismic event identification analysis with MDAC discriminants requires estimated source population means and covariance matrices for the discriminants from each of the possible source types used in our analysis e.g., deep earthquake, shallow earthquake, and explosion.

Descriptors:

• *DISCRIMINATION
• *STATISTICAL PROCESSES
• *SEISMOLOGICAL STATIONS
• *CALIBRATION
• MONITORING
• COVARIANCE
• GROUND BASED
• BAYES THEOREM
• EARTHQUAKES
• AMPLITUDE
• DISCRIMINATE ANALYSIS
• MULTIPLE OPERATION
• SYMPOSIA
• METHODOLOGY
• STATIONS
• MATHEMATICAL MODELS
• NUCLEAR EXPLOSIONS

Subject Categories:

• Seismology
• Statistics and Probability

Distribution Statement:

APPROVED FOR PUBLIC RELEASE