Time-Term Analysis of New Britain - New Ireland Island Arc Structures

Seismic data from the New Britain-New Ireland region are interpreted by the time-term method to give depths to four refractors: (a) the near-surface refractor in the area of the Rabaul Caldera; (b) the basement refractor under the Gazelle Peninsula-southern New Ireland area; (c) the intra-crustal refractor; and (d) the Moho refractor under New Britain, New Ireland, and surrounding waters. The respective least-squares velocities are 4.64±0.08 km s-1, 6.11±0.02 km s-1, 6.84±0.03 kms-1, and 7.92±0.05 km s-1, with the residuals indicating that there is a wider divergence of structure at the Moho boundary than at the upper three refractors.