Davey, F.J.; Smith, E.G.C. 1982 The Wellington seismic reflection survey phase 1, 1979. : . Report / Geophysics Division 187 15 p.
Abstract: During February and March of 1979 a seismic reflection survey was carried out along a line from Palliser Bay to Cook Strait at a point just south of Makara. These measurements formed part of a series of seismic measurements designed to trace a strong seismic reflector, at a depth of about 20 km beneath Wellington, from the Hikurangi Trough to the Marlborough Sounds. This reflector may coincide with the interface between the Pacific and Indian plates under the North Island. The survey was carried out using a variety of land recording instruments. Seismic signals were generated by 25 kg charges of explosives detonated on the seafloor at a depth of about 10 m at two shot points, one near the entrance to Wellington Harbour and the other just south of Makara. The recorded data have been manually digitised to enable a set of seismograms to be produced at consistent scales and amplitudes. Preliminary analysis of the travel time and distance data shows the existence of rocks with P wave velocities of about 4.5, 5.0, and 5.7 km/s at depths of 240 m, 650 m and 2300 m respectively beneath the profile. Seismic reflected arrivals are variable in quality across the profile and are apparently from different horizons for each shot point. For the shotpoint at the centre of the profile the reflection data indicate a reflector at a depth of about 22 km dipping northwest at 15 deg. to the northwest of the shot point and at 8 deg. to the southeast of the shot point. For the shot point at the northwestern end of the profile the data apparently come from an interface at a depth of 18 km dipping at 15 deg. to the northwest
