Infrasonic Observations of the Gas Explosion on April 26-27, 1995

INTRODUCTION It has earlier been shown (Waldemark and Liszka, 1992) that the infrasound generated by burning oil fields in the Persian Gulf could be detected in Northern Sweden at a distance of about 4200 km, According to press news a huge explosion of natural gas occurred on the night of April 26-27 close to the town Uchta (63.59N, 53.55E) in Northern Russia. According to a press release from the Swedish Gas Association, the total amount of gas released in the accident was 3,200 tons. Assuming an energy content of38.8 GJ per 1000 m3 gas and a gas density of 0.624 kg/m! the approximate acoustical power of the source may be estimated. It has been found from infrasonic measurements in Northern Sweden that the total duration of the gas leak was about 81 minutes. The gas flow was therefore approximately 103 m3/sec, driving a flame column a few thousand meters high (according to a press notice) . Assuming that about 1% of the combustion energy was converted into infrasonic energy, the acoustic power of that source was of the order of 400 MW. 'A source with that acoustic power could certainly be detected over a distance of at least 4000 km. In the present paper results of infrasonic measurements of the explosion made in Northern Sweden are reported.