Hull, A.G. 1979 Trig site stability survey report New Plymouth-Castlepoint. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EDS 67 37 p.
Abstract: Part of the Royal Society Earth Deformation Studies Programme is the establishment and reobservation of parts of the 1st order survey network. The survey network New Plymouth to Castlepoint (Fig 1) includes 14 existing 1st order stations and 14 2nd, 3rd and 4th order stations whose reobservations are all planned for 1980. The purpose of the network is to update existing first order triangulation and to establish a pattern crossing the lower half of the North Island which can be used to establish rates and direction of horizontal earth deformation. To ensure that observed changes are the result of crustal movement and not topographic or geological instability it is important that all trig stations are founded in geologically stable sites and an assessment of their stability is carried out. This report assesses the stability of 28 trig stations from New Plymouth to Castlepoint. Criteria for site stability grading are presented in table 1 and are based on field observation of foundation materials, topographic and geological setting. Aerial photographs and existing geological records have been used to supplement field data. Fieldwork was carried out between 8th - 31st October 1979, in conjunction with Lands and Survey staff from Wellington and New Plymouth District Offices (auth)
