OBSERVATORY RECORDS

Evening Post, Volume CXVII, Issue 55, 6 March 1934, Page 8

OBSERVATORY RECORDS

ROUGHLY 100 MILES AWAY

NUMEROUS AFTER-SHOCKS

The observatory records, -which were made available by Dr. Adams at 3 p.m., show that the very first shock was at 11 hours 46 minutes 19 seconds. There was another shock at 11 hours 58 minutes, and a furthei' one at 12 hours 6 minutes. After that there were eight fairly large shocks, which might have been felt by people, or might not, but which left very clearly denned records on the seismographs, and altogether, including these, there were 22 aftershocks, some of which, might be described as -microscopic. Judging from the shocks as recorded the epicentre of the shake must have been some 96 miles from Wellington, and though this is not yet definite, it seems as though the Pahiatua district is indicated. The intensity of the shock in Wellington on the Rossi-Forel scale was roughly 6. The shake has made necessary a great deal of work at the Dominion Observatory at Kelburn, and much of the time of the Government Siesmologist, Dr. Adams, who is short staffed at the moment, is being taken, up In readjusting clocks. Two of the pendulum clocks stopped, and practically every other clock, except the chronometers, suffered slight derangements. These adjustments occupied a considerable time, but with tho help of the ships chronometers, less subject to vibrations and jolts, it w-as possible to work out a time signal for 11 a.m. today. Usually it is the practice to send out a time signal at 9 a.m., but that was impossible today. The effect of the shake on the finer of the seismological instruments was even more marked. The two MilneShaw Seismographs, which will admirably record a shock - at Isevr Caledonia or elsewhere at a great distance, will not stand up to sturdy local shocks, and these were put completely out of adjustment by the shake. The most legible shock visible at the moment was on the Milue-Jaggar machine, which gives a record on a rnai'ked paper disc. This showed a rapid acceleration from the initial tremor to considerable proportions in a short space of time. Some ten minutes after the first shake there was a minor tremor, and following that at a considerable interval a very slight one indeed.