| The goal of this study is the quantification of seismic and infrasound signals from near-surface events. The temporal variation of infrasound detections for seismo-acoustic arrays on the Korean Peninsula are characterized with the adaptive F-detector (Arrowsmith et al., 2009). Infrasound background noise levels affect detection and are shown to be related to wind speed, ocean wave height and local activities near the arrays. Automated detections produced by PMCC (Cansi, 1995) and InfraMonitor (Arrowsmith et al., 2009) are compared to the signals identified by five independent analysts. A regional infrasound source catalog for the western U.S. (November 2010 to October 2012) is produced based on the application of adaptive F-detector and the Bayesian Infrasonic Source Location (BISL, Modrak et al. 2010) to twelve arrays in the region. The infrasound catalog contains 1510 events with repeated events from a number of locations. The majority of events occur during working hours, Monday through Friday, suggesting a human cause. Infrasound signals from a rocket launch and re-entry/explosion, conducted by North Korea on April 13, 2012, were used to further illustrate the detection and location process. Seismic source estimates (based on the Mueller-Murphy model) for the North Korean nuclear explosions in 2006, 2009, and 2013 were developed from regional seismic observations using a grid search approach. The depth ranges are 681-1000 m for 2006, 850-1100 m for 2009, and 750-1150 m for the 2013. The yield ranges are 0.9-1.1 kton for 2006, 3.0-3.5 kton for 2009, and 7.0-9.0 kton for 2013. |
