OLD-TIME UPHEAVAL

Hokitika Guardian, 12 July 1929, Page 2

OLD-TIME UPHEAVAL

WELLINGTON’S GREAT SHOCK. RAISING OF COASTLINE. The reported rise of the ocean bed near Karamea is the subject of an article written by Dr C. A. Cotton, professor of geology at Victoria University College, relating to the great Wellington earthquake of January 23,1855. During this upheaval portions of the coast around Wellington were lifted in some cases nine feet above their normal level. “As is well known,” Professor Cotton says, “tlie very severe earthquake which occurred at Wellington in 1855 was of an unusual kind, in that the disturbed area was situated actually upon an earth-block of land that suffered sudden uplift, the extent of the uplift being estimated by eye-witnesses at five feet at Wellington, increasing to nine feet on the western shore of Palliser Bay. While Wellington cannot escape being occasionally shaken, along with the adjacent parts of. the North and South Islands by earthquakes originating at one or other of the disturbed areas beneath the neighbouring seas — the positions of which have been determined by the late Mr G. Hogben, or in the Amuri district, where the late Mr Alexander M‘Kay determined the origin of the Cheviot earthquake in 1901—the danger of a great disaster was chiefly in a repetition of the uplift of 1855.

MINIMISING THE RISKS. “Such a movement of the land has rarely been observed, hut it is not difficult to imagine the effects of the resulting earth tremors on high buildings situated upon the block that is actuallyjerked upward. Warnings as to the instability of the site of Wellington have been issued from time to time by those who would have to profit from the experiences 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 been more than once destroyed, they are regarded as tlie eroakings 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 earthquake proof building would resist such a shock, or series of shocks, as occurred in 1855. This being the case, it is worth while to inquire whether such an event as that of 1855 is likely to occur again. Such an inquiry attains still greater significance when one 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 useless.

“ The only method of inquiry open to us is to examine what has happened in the past. An uplift of the land leaves very distinct traces of its occurrence. There lies revealed a strip of the former sea bottom, the rocky platform cut by the waves a little below former highwater level, hut now never completely covered; a beach-ridge, 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 of the waves. ■;

; EVIDENCES OF UPLIFT. “ 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, where they have not yet been destroyed by the vandal roadmaker. The uplift of these beaches, rocky platforms, caves and cliffs took place in 1855, however, and there is a notable absence of similar evidence of a series of earlier movements of the mass kind. On the contrary, the heights 'of tlie cliffs and the width of the rocky, platform at their base—for example at the eastern side of Lyall Bay—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 a new era of rapid, spasmodic uplift. We may hope that the former inference, is the true one. On other parts of the shoreline in the immediate vicinity of Wellington there is no evidence to indicate that the land ha not been stable for a very long period as compared with the lives of men. It is only when looked at from the point of view of geological history, which accustoms one to think in millions of years, that the* district can be described as showing evidence of , great disturbance in comparatively recent times.”