Improved, Regional, Seismic Event Depth Estimation

73114S03-I In regions with relatively few seismic stations and small-to-intermediate-magnitude events, traditional location methods frequently fail to provide event depth estimates with the accuracy required for nuclear test monitoring. Therefore, improved algorithms for precise depth estimation from regional seismic array data are needed. This project will develop an innovative three-step procedure to estimate event depth from regional seismic array data. The method will be statistically evaluated with a set of well-located events. Phase I will create a small database of well-located events. A wavelet filtering technique will be used to extract depth phases from the waveform. Phase II will automate the algorithm and prepare it for implementation into an operational testbed. Commercial Applications and Other Benefits as described by awardee: Improved seismic event depth estimates not only should improve the detection and identification of nuclear tests in foreign countries, but also would provide earthquake seismologists the necessary tools to more accurately delineate earthquake faults, thereby, contributing to the mitigation of earthquake hazards. The technique also could be used by gas and oil exploration firms to improve their ability to process seismic data for the discovery of new oil reserves.