Hurst, A.W. 1979 Volcanological observations at Tongariro National Park, 1: Ruapehu borehole tiltmeter, 1975-1978. [s.l.]: [s.n.]. Report / Geophysics Division 149 20 p.
Abstract: A borehole tiltmeter has been operating at a site 5.5 km north of the Crater Lake of Ruapehu since November 1975. There has been little volcanic activity of Ruapehu during this period, and only one possible example of a tilt change related to volcanic activity has been observed. Medium and long term tilt changes were recorded and these can be related to the weather affecting the ground around the borehole