Kainan Maru Seamount lies off the northern end of the Gunnerus Ridgealong the margin of East Antarctica. The seamount is separated from theGunnerus Ridge by only about 15 km. Detailed Hydrosweep multibeamsurveys of the seamount have shown that the seamount rises over3,500 m above the surrounding seafloor, has an oval shape about 60 kmwide and 120 km long, and has a gently sloping summit. The northernand eastern sides of the seamount are steeper than the southern andwestern sides. Many erosional channels cut the northern and easternflanks of the seamount, whereas the western side shows evidence oflarge sediment slides and is more gently sloping. The morphology of theseamount, as observed in the bathymetry and satellite gravity data,suggests that Kainan Maru Seamount may be a detached piece of theGunnerus Ridge that rotated clockwise away from the ridge during therifting of Gondwana in this area.