EARTH MOVEMENTS

Nelson Evening Mail, Volume LXIV, 5 August 1931, Page 3

EARTH MOVEMENTS

ANOTHER BIG SHAKE UNLIKELY

DR MARSHALL’S VIEWS

.‘.‘As .far as the teachings of.the past can tell us, it is not dikely that we will have 'another big earthquake in : New Zealand, seeing that we have had two in recent times,” said Dr. C P. Marshall, of the Department of- 1 Scientific and Industrial Research, when speaking, ;cn “Earthquakes and- their physical Effects” to members of the New Zealand Institute of; Architects at Wellington, states the'•‘Dominion"’ i . . - - • .

Dr. Marshall began his address by; describing earthquake waves. and their movements, and stressed the' distinction between compression waves arid transverse waves. The rumble arid shiver that was felt just before -a big ’quake, he said, was caused by'the compression waves, and the shock itself by the transverse waves. If the centre of the ’quake was far away the shock would not be felt till some appreciable time after the rumble had been heard, but if the centre was close, tile two actions would come practically simultaneously. Earthquakes were very ordinary phenomena, he said. Though in New Zealand a great number were felt, there were tremors in nearly every country in the world, and some countries that had had them with great severity were now practically immune. The two greatest felt in Wellington were those of .1848 and 1855—the latter one had raised the ground five feet, a really gigantic force. There were very few places in the world that had two destructive earthquakes, however, and Wellington had. That, in Iris opinion, would have relieved the earth stress and it see.ried reasonable to think that there would not be any more.

Many people had the habit of saying, on hot, muggy daySj “This is just the weather for an earthquake,” he said; some went further and allied earth-; quakes to an eclipse of the sun or the moon. Dr. Marshall assured his audience that earthquakes were catalogued extremely carefully and from the data available it was apparent that there was no astronomical or meteorological relationship in earthquake frequency. As far as the Napier earthquake was concerned, Dr Marshall said that he was convinced that a great deal .of; the Warn-? that had,been laid at lhe doors of -faulty construction and faulty material in buildings was really attributable to the fact that there was an astounding variation in earthquake intensity in very small distances. In. the Napier ceme : tery, for instance, some of the headstones had been flung long distances by the earthquake, while others, almost adjoining, had barely shifted. The speaker showed a number of lantern photographs of the effects of the earthquake at Napier and further along the coast line.