Crustal and Upper Mantle Structure of the Solomon Islands as Revealed by Seismic Refraction Survey of November-December 1966

Abstract

A seismic refraction survey was carried out in the waters around the Solomon Islands during November and December 1966. Three ships were involved in the survey: two, stationed at the end points of the traverses, acted as recording ships; the third steamed along the traverses and dropped explosives. Reflection profiling and magnetic surveys were simultaneously carried out with the refraction survey. The results show that (a) on the Ontong Java Plateau to the northwest of the islands the crust is about 25 km thick with subnormal crustal velocities; (b) southwest of the New Georgia Islands the crust is thinner than normal and is underlain by a mantle with low velocity; (c) southwest of Bougainville Island the crust is generally of normal oceanic structure underlain by a mantle with low velocity; and (d) mantle material in the Slot is found at a depth of 14 km.