Tsunami Warning System

Press, Volume CV, Issue 30958, 14 January 1966, Page 3

Tsunami Warning System

(N.Z. Press Association) PALMERSTON NORTH, January 13. A scheme to warn residents in coastal districts of the southern half of the North Island of an approaching seismic wave tsunami has been completed by the Ministry of Civil Defence. The Civil Defence Regional Commissioner at Palmerston North (Captain T. D. Herrick) said today that whenever information was received that the risk existed of a -eismic sea-wave reaching New Zealand a warning initiated by the Ministry would be passed through the Post Office tolls

system and police channels to local civil defence officers in towns and counties along the coast

“It will then be the responsibility of the local organisations to pass the warning on to people who live near sea level or who are on beaches which can be reached in time. People will be told to move to higher ground or listen to radio broadcasts,” he said.

The second step would be the broadcasttag of information and instructions to the public. “The standard alarm for a seismic sea-wave is a series of five or more blasts, each of about five seconds duration, on fire sirens.”

The standard alarm could be given also with hand-oper-ated sirens, factory, whistles,

ships’ whistles as well as through loud-hailers. “People hearing the alarm should listen for rad' messages and if they are on the beach, move to high ground. They should make sure their neighbours have heard the alarm as it is most important that everyone should know of the emergency.

Captain Herrick said Tsunami were a very real threat to New Zealand, especially on the east coast. Last year two warnings had been received but neither developed into a dangerous situation. In November, 1964, when Raoul island was erupting, New Zealand was in grave danger of serious damage from such a wave, and in May, 1960, the Chilean earthquakes caused sea-waves which reached New Zealand

and did minor damage in several coastal towns. A total of 66 tsunami occurred in the Pacific Ocean from 1928 to 1963. Of this total three caused slight local damage, 17 caused death or destruction near their source, five were widely destructive and 44 caused no oamage.

Captain Herrick said any earthquake occurring round the perimeter of the Pacific Ocean would be recorded. By using a sea-wave travel-time map the arrival of the wave on the New Zealand coast could be computed.

Such a wave would not be noticed by a ship at sea and would travel at 670 m.p.h. in 30,000 ft of water. “The speed of the wave drops as the water shoals and as this happens the wave grows in size, reaching dangerous proportions near the shore.” *