Infrasound detection of large mining blasts in Kazakstan

We describe infrasonic observations recorded since October, 1997, at the Kurchatov Observatory in Kazakstan from large mining blasts in Kazakstan and Siberia. Seismic signals are regularly recorded on a 21-element cross-array from events located at the Ekibastuz mine, 250 kin NW of Kurchatov. However, associated infrasonic detections are infrequent and appear to be seasonal, with maximum numbers of detections occurring during November to January. Raytracing through model atmosphere temperature and wind profiles predicts enhanced infrasound reception during the winter months, when the prevailing stratospheric winds blow towards Kurchatov. In addition, raytracing confirms that the first infrasound arrivals at Kurchatov propagate through the troposphere and are followed, some 50-70 s later, by a stratospheric arrival.