FRIDAYS EARTHQUAKE.

Marlborough Express, Volume XLIII, Issue 270, 16 November 1909, Page 5

FRIDAYS EARTHQUAKE.

:- v aY re^ttL'xjf, ' *>Ma:y's earthquake, was takeniil Wellington on the Miftfe Seismograph by Mr G. Hogben. Tt shows; (says' the New Zealand Times) that the beginning of the shake was recorded at 9 hours 33 minutes 36 seconds p.m., New Zealand mean time.. The boom swung more, than half wav across the paper, indicating, a distinct' shock. The instrument had been at rest before, as shown by the clear straight line on the left. The\ tremors. continued for many hours afterwards, and had not ceased when the record was taken off next morning at 6.30. Among these tremors were several shakes of smaller' magnitude, the first occurring at 1.57 a.m. on Saturday. The most interesting fact connected with the record is that it shows a tilt of the earth's surface towards the eastern side of the, observatory of a little over half a second of arc. Smaller tilts have faeen observed on at least three previous occasions in New Zealand. First there is the notable one or the earthquake of January 23, 1855, in which there was a .large tilt up on the eastern side and down on the western side. Secondly, at the time of th& Cheviot earthquake, when there was a smaller buj> still very considerable tilt on towards the west. Lastly, on August 9th, 1904, on the occasion of the East Coast earthquake, there was a still .smaller tilt, also towards the west. The direction of the present tilt is therefore in an opposite direction to the former ones. It is also the first tilt which has been associated with an earthquake that probably belongs to the Cook Strait region. In his interesting account of "Earthquakes and Other- Movemerits,'" Mr.Hog'ben remarks:— "On January 23rd, 1855, a sudden elevation of the land took place in the neighbourhood of Wellington : the land rose about eight .feet, : sinking again afterwards three feet, so that the permanent rise was five feet; to the north--..and east of Wellington therise is said to have been greater still —as Imuch as,nine feet on the west side of the Wairarapa Valley. On j the other hand, the west side of < Cloudy Bay, north of Blenheim, was depressed to the extent of five feet. Naturally, such an extensive sudden movement of a large tract of country (4600 square miles, it is estimated) caused a severe shaking of the earth's crust, or earthquake, the vibration or waves of which travelled all over the Colony; other shocks occurred for weeks afterwards, until, indeed, this part of the earth's crust had resumed a more stable position."