Plate tectonics and the Papua—New Guinea—Solomon Islands region

Abstract

The focal mechanism solutions for a number of earthquakes in the New Guinea region are presented. These solutions, together with the results of a previously reported spatial seismicity study, are used to deduce the tectonic nature of the region in terms of plate tectonics, using the geological features of the region as constraints. The region is basically a zone of interaction of the Australian and South Pacific plates. Within this zone are several minor sub-plates referred to as the Solomon Sea, New Britain, and Manus plates. A consistent system of relative velocity vectors has been deduced for these plates. A zone of subduction is apparent under New Britain and the Solomon Islands, a zone of sinistral transcurrent movement operates between the New Britain and Manus plates, sea-floor spreading seems certain in the Woodlark Basin region, and a continent/island arc collision zone exists in northern New Guinea. An interpretation of the Cainozoic history of the New Guinea region is presented.