Scientists pinpoint meteor explosion - 13/07/1999

Scientists have pinpointed the spot where a meteor exploded over New Zealand last week, but cannot say whether any fragments reached the ground.

Terry Webb, a seismologist with the Institute of Geological & Nuclear Sciences Limited (GNS), said the blast was about 25km northeast of the south Taranaki town of Hawera, at an altitude of 37km.

The point of the explosion was calculated by using recordings from nine seismographs from Ruapehu to New Plymouth. The New Plymouth data came from seismographs around Mt Egmont which are operated by the Taranaki Regional Council.

Dr Webb used the speed of sound in air to work out the meteor’s "terminal detonation". However, he emphasised there was a margin of error in the calculations due to variations in air temperature and wind speed.

" This clarifies the location of the explosion that witnesses saw and heard, but it doesn’t tell us the meteor’s trajectory or whether any fragments reached the ground,’’ Dr Webb said.

The information had been shared with numerous researchers both in New Zealand and overseas.

Director of the Auckland Observatory, Ian Griffin, said dozens of people had contacted the observatory saying they had seen the explosion. Observatory staff had thoroughly checked all reports and had come up with what they considered were the 25 most reliable sightings. All 25 accounts tallied with the seismograph derived location.

A United States meteorite dealer has offered up to $US25,000 ($NZ48,000) for any fragments of the meteor that flashed across the central North Island last Wednesday.

John Callan
Communications Manager
Institute of Geological & Nuclear Sciences Limited
Ph: 04-570-1444 (w)