New Britain—New Ireland Crustal Seismic Refraction Investigations 1967 and 1969

The initial interpretation of deep seismic refraction data in the New Britain‐New Ireland region has resulted in generalized crustal crosssections in six areas being defined. In the south‐east Bismarck Sea a single layer crust with a P seismic velocity of 6.9 km s overlies 8.0 km s mantle at 20 km depth. The crust thickens under the Gazelle Peninsula to 32 km in a two‐layer crustal model and this thickness is maintained out to the islands east of New Ireland. In central New Britain a two‐layer crust 29 km thick at the Solomon Sea margin thins to 25 km under Central New Britain with high crustal seismic velocities indicating a high density crust. Further examination of the large amount of data now available in the region is under way and should reveal detailed structure in the upper crust