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Improvements to the Seismic Detection and Location Procedure.
NTIS: PB/84-193713 :49 pages
This report discusses three factors that relate to the seismic detection and location of trapped miners. (1) As part of the modeling procedure to explain the seismic waveforms observed on surface seismic subarrays, the forcetime function of the source must be known. Accelerometer records of a source timber show the force is approximately one-half sinewave and that floor blows have a longer dwell time than roof bolt blows, leading to smaller amplitude for floor blows. (2) Comparisons were made between the least squares and miner location methods using both statistical simulations and actual data. The comparisons showed the methods give similar accuracy for events inside the array with seven subarray arrival times. However, for fewer subarrays, or for events outside the array, the least squares method is more accurate. (3) Refraction surveys to determine the rock velocity used for source location calculations should be approximately 1,200 ft long.
CP; Final Contract Report;
NTIS Accession No.
Penn State Univ.
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division