Alberta bolide of June 1, 1982: interpretation of photographic and seismic records

Abstract

Passage of a bright bolide northeast of Edmonton near midnight on the evening of June 1, 1982, was recorded both photographically by three cameras of the Meteorite Observation and Recovery Project of the National Research Council of Canada and by seismic recording stations at Edmonton and Cold Lake. The photographic data indicate a path towards the northwest at an average height of about 80 km and an average speed of 28 km/s. The Cold Lake data make possible the determination of direction and velocity of approach of the sound wave as well as wave-front curvature in the horizontal plane. The data indicate an essentially zero curvature and a speed across the array of 337.8 m/s for the sound arrival.Wave-front curvature indicates a line source, being the nearly cylindrical shock wave from the hypervelocity bolide. Directions of approach at both Cold Lake and Edmonton, however, seem to indicate a direction more consistent with the end of the brightest segment of the meteor photograph.The discrepancy is not resolved at present, nor is the very slow apparent velocity towards both Cold Lake and Edmonton as derived from the traveltimes to each of the seismic stations.