RISK OF EARTHQUAKES

Dominion, Volume 14, Issue 127, 22 February 1921, Page 4

RISK OF EARTHQUAKES

WELLINGTON’S POSITION

GEOLOGIST’S WARNING

The "Journal of Science” contains an article by Dr. C. A. Cotton, with the heading, -"For How Long Al ill Al ellington Escape Destruction by Earthquake ? Dr. Cotton says the very severe earthquake at Wellington. in 1855 was of an unusual kind, in that the disturbed area was situated actually upon an earthblock that suffered a sudden uplift, the extent of the uplift being estimated by eve-witnesses at sft. at AVellington, increasing to 9ft. on the western shore of Palliser Bay. ’The'danger of a great disaster lies chiefly in a repetition ot the uplift of 1855. It is not difficult to imagine the effects of the resulting earth-tremors on high buildings situated upon the block that is actually jerked upward. AVarnings as to the instability of the site of AVellington have been issued fioin time to time by those who would have us profit from the experience of mankind that where destructive earthquakes have occurred More, 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 the croakings of confirmed pessimists. Few attempts have been made in AVellington to build so as to minimise earthquake risk, and it is very doubtful whether any tvpe of relatively earthquaae-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; and 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 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 high-water level, but now never completely covered; a beacnridge. or storm beach, no longer within reach of storm waves, so that it gradually becomes covered with vegetation; and wave-ent cliffs and sea caves also beyond the reach of the waves. Such evidence of uplift may bo seen at many places along the shore in the neighbourhood of AVellington, and best of all along the strip of beach extending southward from Breaker Bay. Seatoun The upliftof these beaches, rocky platforms, caves, and cliffs took place in 1855, however, and there is a noticeable abssnee of similar evidence of a series of 111 ments of the same kind. On thes 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 mav infer either that the Movement which took place in 1855 was an isolated phenomenon or else that it 'naugurated a new era of rapid spasmodic uphft. M e may hope that the former inference is the true one.