The study of Energy Release and Seismicity in the South West Pacific (continued) : The objective of this study is to determine the dynamics and structure of the New Hebrides Island Ridge and its active marginal zone. Initial field work began in 1976 with a series of seismic experiments. The experiments, a series of short refraction profiles using small air-gun source was obtained in the central New Hebrides. In 1977 additional refraction profiles were obtained using air-gun and explosive sources, and a network of eight ocean-bottom seismic stations was installed in the south central New Hebrides to monitor local earthquakes. Further refraction work took place in 1978 and into the following years.