The objective of the study is to investigate crustal accretion styles and parameters in backarc setting and their differences from mid-ocean ridges. The study has implications for ophiolites that are presumed to be generated in backarc environments. The sutdy will also test various models of tectonic history of the Lau spreading center area. A multichannel seismic reflection survey of the Lau Basin on Ewing with a 4 km-160 channel streamer over 9 acquisition days will be undertaken.