LLNL Location and Detection Research

• Main Authors: Myers, S C, Harris, D B, Anderson, M L, Walter, W R, Flanagan, M P, Ryall, F
• Language: unknown
• Published: 2021
• Subjects: 45 MILITARY TECHNOLOGY; WEAPONRY; AND NATIONAL DEFENSE; 58 GEOSCIENCES; ALGORITHMS; CALIBRATION; DETECTION; EPICENTERS; EXPLOSIONS; IRON; METRICS; MINING; NEVADA TEST SITE; NUCLEAR EXPLOSIONS; SCREENS; SEISMIC EVENTS; VALIDATION; WAVE FORMS; Arctic; Kola Peninsula; Khibiny; Kovdor; Fennoscandian; kola peninsula
• Online Access: http://www.osti.gov/servlets/purl/15004853; https://www.osti.gov/biblio/15004853

We present two LLNL research projects in the topical areas of location and detection. The first project assesses epicenter accuracy using a multiple-event location algorithm, and the second project employs waveform subspace Correlation to detect and identify events at Fennoscandian mines. Accurately located seismic events are the bases of location calibration. A well-characterized set of calibration events enables new Earth model development, empirical calibration, and validation of models. In a recent study, Bondar et al. (2003) develop network coverage criteria for assessing the accuracy of event locations that are determined using single-event, linearized inversion methods. These criteria are conservative and are meant for application to large bulletins where emphasis is on catalog completeness and any given event location may be improved through detailed analysis or application of advanced algorithms. Relative event location techniques are touted as advancements that may improve absolute location accuracy by (1) ensuring an internally consistent dataset, (2) constraining a subset of events to known locations, and (3) taking advantage of station and event correlation structure. Here we present the preliminary phase of this work in which we use Nevada Test Site (NTS) nuclear explosions, with known locations, to test the effect of travel-time model accuracy on relative location accuracy. Like previous studies, we find that the reference velocity-model and relative-location accuracy are highly correlated. We also find that metrics based on travel-time residual of relocated events are not a reliable for assessing either velocity-model or relative-location accuracy. In the topical area of detection, we develop specialized correlation (subspace) detectors for the principal mines surrounding the ARCES station located in the European Arctic. Our objective is to provide efficient screens for explosions occurring in the mines of the Kola Peninsula (Kovdor, Zapolyarny, Olenogorsk, Khibiny) and the major iron mines of ...