THE BIG QUAKE

Hokitika Guardian, 17 June 1930, Page 5

THE BIG QUAKE

LAST YEAR’S DISASTER

At about 10.15 a.m. on June 17th

last year a prolonged and alarming shock, thoroughly frightened the people of. this district, and the shaking was accompanied by noises which were tenible in the extreme. News filtered through slowly from other West Coast districts, and it was not until the following day that the full magnitude of the disturbance was realised, and lor days news was received piecemeal Rom the stricken area. The earthquake was felt in varying degrees intensity all over the Dominion.

During the year' much has been done to effect repairs to buildings, bridges, and roads in the devastated areas, but I still visitors can see huge sears on the landscape, slips and wh|t>le countrysides levelled and covered with debris, ,new being overgrown, which are silent and terrible testimonies to that terrific upheaval. There are many months ahead yet, which will have to be devoted to repair work, and some of the damgo is irreparable. Following the initial relief in which aeroplanes, and telephonic, telegraphic . and wireless communication played such a big part, the Public Works Department was.faced with the huge task of re-oponiug highways for the Buffer,' Gorge and other maiu ’rputes were ft* mass of slips, During the year the approximate ox- i penditure by the Government through# the Public Works ‘ Department in re- f storation, has been £138,250. The details are as follows:

■ Reconstruction and clearing of settlement roads, including repairs to, and erection of bridges, £19,400. Similar work jon main .highways,, £107,000.

Contribution to repair Westport Borough water service and, Murchison power-house, £3256. Restoration work at public hospitals, Nelson, Westport and Greymouth £4800.,

Repairs to various post offices, police stations, and other public buildings in the area, £2950. Rebuilding of wharf at Karamea (still in,progress) £490. In addition to the above, the Treasury has administered the expenditure of the Earthquake Relief Fund, established for the purpose of relieving the distress of private individuals. OPINIONS OF GEOLOGISTS.

A geological survey has been made of most of the area near the'supposedcentre of the earthquake, and more, work of investigation will be carried out. Geologists agree that the upheaval was due to the release of static stress between contiguous earth-blocks. This release took place on the White Creek fault-plane, and probably simultaneously" on ■or near the Kongnlni : fault-plane, which is parallel and closd to the. west coast of the Nelson Pro- ~ vince.' Other'fault's' ihthe northerly part of the South Island, allowed synn pathetic adjustmets of earth-stresses, • after-shocks being generated on the , other fault-planes. „ , ■ "‘The M : ,urchison .earthquake^”;!recently reported Messrs H. T. Feirai and L. I. Grange, of the Geological Survey Department, “seems to have been generated at an apparently dSimant fault that revived and allowed an earth-block to rotate. The recorded uplift of 14ft-9m caused a block oi countrvto tilt eastward on the cpn|ex side of the fault. The "'Murchison;,: earthquake seems to differ from other earthquakes experienced in New Zealand in that it was in the nature ot, a double earthquake with foci on tuq nearly parallel lines of weakness, namely the White Creek and Kongahu fault-zones; but like the others, it was followed by aftershocks, the foci o, which migrated to and fro along major fault-planes or shifted to other place of fracture. The result was the-north-west corner of the South Island continued to creak like the deck of a ship for weeks after the first disturbance took place. The after-shocks were a blessing in disguise, for they indicated that earth-stresses were being released rather than accumulated, and that the longer they continued; ~ the less likelihood there was of a repetition of the first severe earthy, quake.” The same authorities ascribe th; marked differences in the extent odamage that resulted from the Murchi son earthquake to the deflection and, delays in their passage of Earthquake, vibrations owing to the varying geo logical structure of the rocks. For in stance the Wnirau fault-plane probably deflected the vibrations away from Marlborough, and thus protected Bleu heim, while the position of the War; mea fault-plane adversely affected Nelson. , ' ' ' ■

The intensity of the earthquake theestimate as VIIT. on the Rossi-Fore scale, X. being the maximum. ‘‘Tingreat landslips gave the impression s that this figure was exceeded,” they say, “but it must be remembered that the slips took place from precipitous hillsides, where slips frequently on : h cur, especially during wet weather.” '|g