RISK OF EARTHQUAKES

Hokitika Guardian, 26 February 1921, Page 1

RISK OF EARTHQUAKES

WELLINGTON'S POSITION. CEO LOCH ST’S WAHNINO. The “Journal of Science” conlaiiis an article by Dr A. Cotton, with the heading, ".For How Long Will Wellington Escape Destruction b,v Earthquake?” Dr Cotton sttvs the very severe earthquake at Wellington in 1 Hufi was of tin unusual kind, in that the disturbed area was situated actually upon an eiiithhloek that suffered a sudden [ uplift, the extent of the uplift being estimated by eye-witnesses at Alt at Wellington, increasing to lift on the western shore of Palliser Hay. The danger of a great disaster lies chiefly in a repetition of the uplift of lHoo. It is not difficult to imagine the effects of the resulting earth tremors on

high buildings situated upon the block l!iat .is actually jerked upward. Warnings as to the instability ol' the site of Wellington have been issued from time to time by those who would have us profit from the experience of mankind that where destructive earthquakes have occurred before, there they will occur again ; but these have fallen on deaf ears, or, just as in San Francisco, a city that has I men more than once destroyed, they are regarded as the croakings of confirmed pessimists. Few attempts have been made in Wellington to build so as to minimise earthquake risk, and it is very doubtful whether any type of relatively earth-quake-proof building would resist such a shock, or series of shocks, as occurred in 1855. i

This being t-lic case, it is worth while to inquire whether such an event as that of ]Boo is likely to occur again; and such an inquiry attains still greater significance when ona considers that each such rise renders the entrance to Port Nicholson shallower, and that a continuance of such shallowing would soon render the harbour entirely use-

less. The only method of inquiry is to examine what lias happened in the past. An uplift of the land leaves very distinct traces of its occurrence.- There lies revealed a strip ol the former seabottom, the rocky platform cut by the waves a little below former high-water level, hut now never completely covered ; a beaehridge, or storm beach, no longer within reach of storm waves, so that it gradually becomes covered with vegetation; and wave-cut cliffs and sea caves also beyond the reach ol the waves. Such evidence of uplift may be seen at many places along the shore in the neighbourhood of Wellington, and best of all along the strip of beach extending southward from Breaker Bay, Seatoun. The uplift of these beaches, rocky platforms, caves, and cliffs took place in 1855, however, and there is a noticeable absence of similar evidence of j, series of earlier movements of the same kind. On the contrary, the height of the cliffs and the width of the rocky platform at their base indicate that for a long period prior to 1855 the relative levels of sea and land remained

constant. This is a .hopeful sign, for from it we may infer either that the movement which took place in 1855 was an isolated phenomenon, or else that it inaugurated n new era of rapid spasmodic uplift. We may hope that the former inference is the true one.