Rise - Kaibou (English spelling) rise

Japanese: 海膨 - かいぼう（英語表記）rise

A long, wide seafloor rise with a gentle slope. The most famous is the East Pacific Rise. The Northwest Pacific Rise is a typical example in the seas off Japan. It is thought that when the speed of the plates at the ridge is slow, it becomes a seafloor rise, and when it is fast, it becomes a ridge. A seafloor rise is a long, wide rise that rises above the ocean floor, and has relatively gentle and flat sides. A narrow rise with a steep slope is a ridge. There are many shallow earthquakes in the center of the rise, and the heat flow value is much higher than that of an ordinary ocean floor. The thickness of the crust is about 5 km at the center, which is thinner than that of an ordinary ocean floor. The properties of the material that composes the mantle are also somewhat different. From these points, it is interpreted as the rising part of the thermal convection that occurs in the mantle. Therefore, it is thought to have almost the same origin as the Mid-Atlantic Ridge. The northern end of the East Pacific Rise meets the coast of Mexico, and it is possible that it extends further along California to Alaska.

Source: Asakura Publishing Dictionary of Petrology Information

Japanese:

緩やかな斜面で盛り上がった幅広く長い海底の高まり．最も有名なのは東太平洋海膨である．日本近海では北西太平洋海膨が典型的な例である．海嶺におけるプレートの離反速度によって，速度が遅いときには海膨となり，速いときには海嶺となると考えられている．海膨は大洋底にそびえる長大な幅の広い高まりで，比較的傾斜が緩やかで平らな側面を持っている．傾斜が急な斜面をもつ幅の狭い高まりは海嶺である．海膨の中心部には浅発地震が多く,熱流量の値が普通の大洋底よりもはるかに高い．地殻の厚さは中心部で5km程度で，普通の大洋底よりも薄くなっている．マントルの構成物質の性質も多少異なっている．これらのことから，マントル内で起こる熱対流の上昇する部分にあたるものと解釈されている．したがって大西洋中央海嶺とほぼ同じ成因を持つと考えられる．東太平洋海膨は，その北端がメキシコの海岸に交わり,さらにカリフォルニアに沿ってアラスカまで延びている可能性がある．

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