Tamu Massif is a seamount in the northwest Pacific Ocean, sitting atop a triple junction of mid-ocean ridges. Tamu Massif is located in the Shatsky Rise about 1,600 km east of Japan. The massif covers an area of about 553,000 square kilometres. Its summit is about 1,980 m below the surface of the ocean, and its base extends to about 6.4 km deep. It is about 4…Tamu Massif is a seamount in the northwest Pacific Ocean, sitting atop a triple junction of mid-ocean ridges. Tamu Massif is located in the Shatsky Rise about 1,600 km east of Japan. The massif covers an area of about 553,000 square kilometres. Its summit is about 1,980 m below the surface of the ocean, and its base extends to about 6.4 km deep. It is about 4,460 metres tall.