WHEN TAUPO TREMBLED

Taupo Times, Volume II, Issue 81, 5 August 1953, Page 1

WHEN TAUPO TREMBLED

THE 1922 EARTHQUAKES Toward the end of May, 1922, a slight earthquake felt generally in Taupo provided conversation for a few days among the local residents. Early in June the metropolitan daiiy papers of Auckland and other cities carried big headlines announcing a "Night of Terror in Taupo." So severe and numerous were the earthquake shocks that Post Offiee officials were given permission to leave, were it considered that further danger threatened. Many of the initial shocks would have caused considerable damage but for one thing. That was the fact that^ the heaviest vibrations were vertical in their movement, due to the close proximity to Taupo of the subterranean centres from which the shocks were propagated. As a result of this, no chimneys in Taupo were thrown down, although a number were cracked at the neck. The violent initial shocks were thought by some to presage a volcanic outburst, but old residents recalled even more violent shocks felt over a considerable period some twenty odd years earlier. On the earlier occasion the centre of the disturbance had been south-east of Taupo, and at least one fault scarp was observed on the Kaingaroa Plains with a depression of six feet. Interesting Phenomena Once the first alarm was overcome, the most serious effect of the continued series of earthquakes was the difiiculty on many nights of getting undisturbed sleep. At the Taupo School pupils were soon observed, when the preliminary quickly increasing rumble of a big 'quake was heard, to sit up straight, so that they could feel the back of the forms hitting their backs when the "shake" came. During the heavier early shocks in June a certain amount of damage was done to vases, crockery, and goods on shelves in stores and hotels. Residents soon placed all such objects on the floor to avoid, further iosses. It was noted that the preliminary rumbling noises preceding big shocks came from the west, and it was secn that the centre of the disturbance lay in that direction. One day in June, Mr Arthur Grace^ of Taupo, rode with a friend over the saddle in the hills west of Nukuhau village, and down into the Whakaipo Bay area, pig hunting. As they rode along the flat country west of the range, they heard the sound and then felt the movement of a strong *quake, Suddenly, near by on ihe flat, they sawT bursting out of the ground. what they soon realised were columns of water, shooting up to a height of several feet. Their first thought. that this might be the beginning of volcanic activity, was soon dissipated as they saw their pig dogs rush up and commence lapping greedily at the obviously cold water. Later, riding along the Whakaipo beach, they sawT that many similar water jets had come up in the lake, forming crater-like holes. The jets on the land brought up large quantities of fine pumice sand. Such temporary fountains, often caused by earthquakes, are a secondary effect of the shaking, which by consolidating the ground may put pressure on under-lying beds which are impervious to water. Water lying above is forced by the pressure to find outlets upward. Similar foun- 1 tains were observed at Oruanui on several occasions in 1922. ■r ; Widespread Subsidence When Mr Grace and his companion approached the top of the range, they found, crossing their track, a crack in the ground several inches m width. on the western side of which the country had dropped twTo feet. This fault scarp ran on either side as far as they could see, parallel with the main direction of the range. Some time later, it was reported by hunters visiting the area that the beach at Whakaipo had sunk, and a visit of inspection made by launch showed this to be correct. (See picture, this page). The shore-line in WThakaipo Bay had been depressed some ten feet. Inland of the mouth of the Mapara Stream, a fault scarp had appeared running inland parallel with the line M the eastern shore of the bay. The

land west of this scarp was depressed as much as ten feet in places, and I all along the base of the scarp the ground was torn and broken in a band ten to twelve feet wide. A similar scarp, west of the stream in Whangamata Bay, with a depression of two feet on its eastern side, appeared to mark the western boundary of the depression so far as it affected the lake shores. Evidences of depression were noted northward in the Mokai bush and near Oruanui. From the cliffs on the western shore of Whakaipo great rock slides had been sent- thundering into the water. The lake itself is recognised by geologists as an area of collapse, connected with past volcanic eruptions, and is bounded nearly all round by fault scarps, which determine many of its shore-lines. The subsidence of 1922 was thus a graphic illustration of the manner in which the lake has reached its present size. Had the subsidence occurred a few miles further east, in Tapuaeharuru Bay, where the Waikato River leaves the lake, the lake level would have been lowered permanently by ten feet. j