Application of Physics-Based Underwater Acoustic Signal and Array- Processing Techniques to Infrasound-Source Localization

摘要

The purpose of this project is to apply physics-based signal and array processing techniques, recently developed in the area of underwater acoustics, to atmospheric infrasound data and co-located seismic field data. The source of the infrasound data is the newly installed International Monitoring System (IMS) infrasound station at Pinon Flat (PFO). The seismic data are being collected by the Southern California ANZA seismic network. Installation of the eight sensors that comprise the infrasound station at PFO was completed by mid April of this year. The space filters of the array (18 m for the inner centered triangle elements and 70 m for the outer centered triangle elements) also are nearly all in place. Preliminary data collected by this array contain some signals with significant spatial coherence across the array aperture. In particular, a large event with high signal-to-noise ratio was recorded on 23 April. Analyses of the arrival structure of this signal are presented in this paper. In addition, the spatial and temporal properties of the background noise in relation to the local environmental conditions are discussed. A focused experiment involving the temporary installation of additional infrasound sensors to provide larger array aperture is being planned for this summer. A description of the planned experiment is presented below.