Tamu Massif is an extinct submarine shield volcano in the northwest Pacific Ocean, with the characteristics of a hybrid between a mid-ocean ridge and a shield volcano. On 5 September 2013, researchers announced that it could be a single volcano which, if corroborated, would make Tamu Massif the largest known volcano on Earth. Tamu Massif is located in the Shatsky Rise about east of Japan. The volcano, which comprises the entire Shatsky Rise, covers an area of about . Its summit is about below the surface of the ocean, and its base extends to about deep. The volcano is about tall.