Laslo G. Evers, Lars Ceranna, Hein W. Haak, Alexis Le Pichon, and Rod W. Whitaker
A seismoacoustic analysis of the gas-pipeline explosion near Ghislenghien in Belgium
Bulletin of the Seismological Society of America (April 2007), 97(2):417-425

Abstract:
A high-pressure gas pipeline exploded near Ghislenghien in Belgium, on 30 July 2004. Seismic energy of this event was recorded at three nearby seismometers. The origin time of the explosion was determined by analyzing the Rayleigh waves and found to be 06h55m27+ or -2sec coordinated universal time (UTC). Ground truth of the explosion was invoked to assess the accuracy of the location derived from infrasound data recorded over Western Europe. Different infrasonic phases were identified by using array-processing techniques and raytracing through atmospheric models. The analysis showed that the derived location was situated 13 km from the true location. The total area of the uncertainty ellipse, or area to be searched if the source was of unknown origin, was 690 km ² . After the origin time and location, the yield was calculated by comparing infrasonic stratospheric amplitudes with those from a high-explosives dataset and was estimated at 40.9 tons high- explosives equivalent. In summary, this study illustrates the capability of seismic and infrasound data in forensic investigations. Furthermore, the potential of infrasound as a monitoring or verification technique is addressed.