Determination and Statistical Analysis of Infrasound Sources Near Socorro, New Mexico

Thursday, 18 December 2014
Tierney Larson, Yale University, New Haven, CT, United States, Jonathan M Lees, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, Daniel C Bowman, UNC Chapel Hill, Chapel Hill, NC, United States and Kyle Richard Jones, Sandia National Labs, Albuquerque, NM, United States
Data collected from 2010 to 2014 at a seismo-acoustic array located outside Socorro, New Mexico provides the grounds for investigating atmospheric radiation of acoustic waves in the area. We extracted 698 impulsive signals (less than five seconds duration) as well as numerous longer period signals, likely trains or other vehicular noise in the region. Using arrival time differences, we derived three-dimensional incidence vectors of infrasound arrivals by calculating azimuth and inclination angles for a sorted group of 661 well-recorded impulsive signals (179 in 2010, 220 in 2012, 262 in 2013). During this period, impulsive sources arrive at the array from an average azimuth angle of 272.4 degrees. Two main clusters of events can be seen each year: the densest cluster spans the azimuth range 250.96-277.18 degrees, while the second cluster spans 294.33-336.35 degrees. Inclinations for both of these clusters are relatively low, as the main cluster spans 16.1-24.68 degrees and the second spans 4.69-18.44 degrees. The main cluster corresponds to the location of The Energetic Materials Research and Testing Center (EMRTC), which detonates regularly scheduled explosions and is located at an azimuth of 266 degrees with respect to the array. The second cluster lies to the north of the EMRTC range, but the source of these signals is unknown and requires further investigation. Signals associated with other sources, most likely mining explosions, appear each year emanating from south of EMRTC. Additionally, two minor clusters at low azimuth angles and high inclinations are observed, possibly originating from a number of sites including Kirtland Air Force Base, Sandia National Laboratories, and White Sands Missile Range. Waveform cluster analysis suggests distinct waveform similarity associated with specific sources.