Methods for Improving Seismic Event Location Processing

Abstract

Public feporting bwden for this collection of infomnatton is estimated to average 1 hour per response, including the lime for reviewing instructions, searching existing data sources qatherinq and maintarni^ >K data needed and compiebng and reviewing ftBcollecton of infonnaton. Send comments regarding this Iwrden esSmate or any other aspect of this collerfon of iiSomiation hSudSSorTfo? »^? *^ this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (070«18^1215 JeffeiBon Davis High^rsSS Srton VA ^nS"^ 4302. Respondents should be aware that notwithstanding arty other provision of law, no person shall be sutiject to any penalty for failing to ^DIV with a con2*onrfW^L«^^ lfZ2. ^^ ^°2-valid OIVIB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.any penanyror railing to comply with a coHecbon of infoanabon if it does not display a currently REPORT DATE (DD-MM-YYYY) 03-11-2003 REPORT TYPE REPRINT TITLE AND SUBTITLE Methods for Improving Seismic Event Location Processing DATES COVERED (From -To)6.AUTH0R(S) C. H. Thurber, W. Du, H. Zhang and W. J. Lutter PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)University of SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)Air Force Research Laboratory 29 Randolph Road Hanscom AFB MA 01731-3010 DISTRIBUTION / AVAILABILITY STATEMENTApproved for Public Release; Distribution Unlimited. ,-«»-SPUNS(»^ONITqR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) I AFRL-VS-TR-2003-1603 SUPPLEMENTARY NOTES ~ "--REPRINTED FROM: PROCEEDINGS OF THE 25™ SEISMIC RESEARCH REVIEW -NUCLEAR EXPLOSION MONITORING,'BUILDING THE KNOWLEDGE BASE', 23-25 September 2003, Tucson, AZ pp 342-351. 14. ABSTRACT Our research program consists of four components, each involving some aspect of multiple-event analysis: (1) high-precision waveform cross-correlation (WCC) for arrival time estimation, (2) robust event clustering, (3) waveform decomposition and source wavelet deconvolution reshaping, (4) double-difference (DD) multiple-event locations and tomography. Our research focused initially on the development and testing of these seismic analysis methods using -ground-truth" (GT) datasets at different scales (local and regional), and is being followed by the application of these methods to a "test bed" regional-distance seismic dataset including tests on real-time and simulated real-time data streams. Here we highlight some of the more significant project achievements from components 1, 2 and 4. SUBJECT TERMS ~ " Seismic events ABSTRACTOur research program consists of four components, each involving some aspect of multiple-event analysis: (1) highprecision waveform cross-correlation (WCC) for arrival time estimation, (2) robust event clustering, (3) waveform decomposition and source wavelet deconvolution reshaping, (4) double-difference (DD) multiple-event location and tomography. Our research focused initially on the development and testing of these seismic analysis methods using "ground-truth" (GT) datasets at different s...

Global Ground Truth Data Set with Waveform and Arrival Data

“…In most local applications (e.g. Shearer, 1997;Thurber et al 2003) a heuristic approach is used to select an operational correlation threshold that was then demonstrated to be fairly robust at screening out the less reliable differential measurements. The relative uniformity of these data sets (all simple local P arrivals, typically only involving single-or three-component short period data) allowed for the selection of a single uniform correlation threshold without adversely affecting the results.…”