With more than 1,000 islands comprising the archipelago, it has a coastline of 34,390 kms. The coastline is a combination of steep cliffs and beaches. Long a sea-faring society, Japan has a food self-sufficiency of only 50%, but boasts the world's largest fish catch of more than 10 million metric tons per annum (1991 figures).

The Japan islands lie at the point where three tectonic plates meet - the Eurasian plate, the Pacific plate and the Philippine plate. The friction and movements between these three plates makes Japan highly susceptible to earthquakes and consequent tsunamis (or tidal waves). The Great Hanshin earthquake that struck Kobe recently is an example of this vulnerability.

On the Pacific side of Japan, the continental shelves cover an average distance of 200 kms before plunging more than 6,000 meters (9,000 to 10,000 meters in the trenches) in the deep sea area. There are three important trenches in the area - Kuril Trench to the north, Japan Trench off Tokyo, and Izu-Bonin Trench towards the south. Another trench, the Nansei Shoto Trench runs between Okinawa and Taiwan further south. Trenches, found in the lowest parts of the earth's surface, are formed by the subduction of one plate below the edge of another, causing major earthquakes periodically.

The meeting of plates and trenches also produces an interesting set of ocean floor phenomena, such as thermal vents (which support a peculiar set of lifeforms, some of which can survive in temperatures as high as 90 degC!), hydrothermal deposits, ocean currents etc. Trenches have also been a focus of interest for earthquake prediction.

In general, ocean research in Japan has focussed on several issues: