<P> The Japan Trench is an oceanic trench, a part of the Pacific Ring of Fire, in the floor of the northern Pacific Ocean off northeast Japan . It extends from the Kuril Islands to the Bonin Islands and is 10,554 metres (34,600 ft) at its deepest . It is an extension of the Kuril - Kamchatka Trench to the north and the Izu - Ogasawara Trench to its south with a length of 800 km (500 mi). This trench is created when the oceanic Pacific plate subducts beneath the continental Okhotsk Plate . The subduction process causes bending of the downgoing plate, creating a deep - sea trench . Continuing movement on the subduction zone associated with the Japan Trench is one of the main causes of tsunamis and earthquakes in northern Japan, including the megathrust Tōhoku earthquake and resulting tsunami that occurred on 11 March 2011 . </P> <Ul> <Li> On 11 August 1989, the Shinkai 6500 three - person submersible descended to 6,526 m (21,411 ft) while exploring the Japan Trench . </Li> <Li> In October 2008, a UK - Japan team discovered a shoal of Pseudoliparis amblystomopsis snailfish at a depth of approximately 7,700 m (25,300 ft) in the trench . These were, at the time, the deepest living fish ever filmed . The record was surpassed by an unidentified type of snailfish filmed at a depth of 8,145 metres (26,700 ft) in December 2014 in the Mariana Trench, and extended in May 2017 when another unidentified type of snailfish was filmed at a depth of 8,178 metres (26,800 ft) in the Mariana Trench . </Li> </Ul> <Li> On 11 August 1989, the Shinkai 6500 three - person submersible descended to 6,526 m (21,411 ft) while exploring the Japan Trench . </Li> <Li> In October 2008, a UK - Japan team discovered a shoal of Pseudoliparis amblystomopsis snailfish at a depth of approximately 7,700 m (25,300 ft) in the trench . These were, at the time, the deepest living fish ever filmed . The record was surpassed by an unidentified type of snailfish filmed at a depth of 8,145 metres (26,700 ft) in December 2014 in the Mariana Trench, and extended in May 2017 when another unidentified type of snailfish was filmed at a depth of 8,178 metres (26,800 ft) in the Mariana Trench . </Li>

About how deep is the japan trench relative to the continental shelf closer to land