EXPLANATION OF BOMB EXPLOSION

Press, Volume C, Issue 29657, 30 October 1961, Page 14

EXPLANATION OF BOMB EXPLOSION

(New Zealand Press Association)

WELLINGTON, October 29 The explosion of a 50megaton bomb would mean that for the first time man , had created an explosion equivalent to one of nature’s •, greatest major earthquake. Dr. M. F. Evi- , son, superintendent of the Seismological Observatory, Department of Scientific and Industrial Research, said yes- - terday. Dr. Evison said that a 50megaton bomb would produce as much energy as a magnitude-eight earthquake. The Napier earthquake of 1931 was slightly less than this, with a magnitude of 7|. The seismological observatory at Wellington had not actually registered any tremor* attributable to the ! recent bomb test in the Soviet Arctic. This could be explained quite simply, he said. Shocks would be felt at a range of 10.000 miles from the initial blast, but Wellington came ' closer to the likely “bomb site” by 500 miles. In other words. New Zea- ; land was within a “show , zone” and did not record the waves produced by even a

natural earthquake occurring at the same distance. Were New Zealand an exact 10,000 miles from Novaya Zembla, seismic instruments here would pick up the transmitted wave from an explosion quite strongly. The tremors radiated from a blast of this magnitude would pass right through the centre of the earth. The core of the earth actually deflected the shock waves in much the same way as a lens deflected and focussed rays of light “New Zealand is not ‘in focus,’ and we cannot pick urn the waves radiated from the Russian experiments.” said Dr. Evison. A proposal to introduce pasteurised milk to Queenstown was defeated at a poll there at the week-end. Two hundred and fifteen opposed pasteurisation. 99 favoured it and two were informal. On* hundred and seventeen postal votes are still to be counted. At a poll In the Queenstown-Frankton area of the Lakes County, pasteurisation was defeated by 53 votes to 22—(PA.)