Comprehensive Seismic Detection and Estimation Using Matched Field Processing
Abstract
Empirical Matched Field Processing (EMFP) is a narrowband method for signal detection and estimation which recognizes a characteristic phaseand amplitude structure over a sensor array. EMFP can provide enhanced detection capability for signals of special interest from a target sourceregion and we here explore its application as a comprehensive front-end detector for general seismic signals. On small aperture seismic arrays, wedemonstrate that a relatively small number of matched field templates are required to cover the parameter space of anticipated signals. In addition,estimates of apparent velocity and back azimuth made directly from the empirical steering vectors are likely to be more accurate than classical f-kestimates since bias from path and near-receiver characteristics is corrected for empirically. On larger aperture arrays, more templates are requiredto cover parameter space. On seismic arrays for which signal coherence in the frequency band of interest is poor, a given matched field detectorwill provide a very signal-specific detector and vast numbers of templates are needed for a comprehensive detector. We demonstrate how classicalslowness estimates for high frequency signals can be enhanced by considering only selected sensor pairs. Similarly, by limiting the influence ofcorrelations between the most distant sensors in the generation of the matched field templates, the footprint of matched field detectors may bebroadened to be less source-specific. EMFP detectors can confidently identify characteristic phase shifts for low SNR signals and we demonstratedetection of the small event at or close to the DPRK nuclear test-site using matched field templates from previously observed events.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 18, 2017
- Accession Number
- AD1056994
Entities
People
- David B. Harris
- Douglas A. Dodge
- Steven J. Gibbons
- Tormod Kvrna