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 (990 mi) east of Japan. The massif covers an area of about 553,000 square kilometres (214,000 sq mi). Its summit is about 1,980 m (6,500 ft) below the surface of the ocean, and its base extends to about 6.4 km (4.0 mi) deep. It is about 4,460 metres (14,620 ft) tall.