Earth Planets Space, Vol. 61 (No. 2), pp. e1-e4, 2009E-LETTER
Il-Young Che, Jin Soo Shin, and Ik Bum Kang
Earthquake Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon, Korea
(Received August 14, 2008; Revised December 8, 2008; Accepted December 23, 2008; Online published February 5, 2009)
The aims of this study were to develop an improved method using infrasound observations at multiple seismo-acoustic arrays for locating small-magnitude surface explosions at regional distances and to apply the method to ground-truth blasting events for validation. The location method is based on a nonlinear grid search using the travel times and back azimuths of infrasonic signals generated from the surface explosions and on seismic parameters that are independently determined by routine seismic monitoring systems. Specifically, the method utilizes wind-corrected infrasonic azimuths in grid searching to constrain the grids according to nearness to feasibly real observations. Ground-truth events were recorded by a seismo-acoustic station temporarily operated inside an open-pit mine and then used to investigate the improvement by the location method. The method improved the locating of ground-truth events by approximately 50% compared to the seismic location results. Surface explosions generating both seismic and infrasonic signals could be located independently by the seismic location, infrasonic-azimuth intersection, and seismo-acoustic location method, respectively. This method can be applied to automatic seismic/infrasonic monitoring systems as an additional location tool for explosion-induced seismic events, allowing for simultaneous monitoring for surface explosions and reduced risk of false location results.
Key words: Seismo-acoustic, surface explosion, grid search.