千叶近海沉积盆地位于日本弧东北部的南部弧前。ＭＩＴＩ（日本国际贸易和工业部）的地震剖面中存在似海底反射层（ＢＳＲ）（图１）。下面讨论其地质背景和成因。１　千叶近海沉积盆地的ＢＳＲ１９７４年Ｔｅｉｋｏｋｕ石油公司和海湾石油公司在房总半岛东部陆架小于１０００ The Chiba offshore depositional basin is located in the southern arc before northeastern Japan. The Seabed Reflective Layer (BSR) exists in the seismic section of MITI (Japan’s Department of International Trade and Industry) (Figure 1). The following discusses the geological background and causes. 1 Chiba offshore depositional basin of BSR 1974 Teikoku Oil Company and Gulf Oil Company in the Housing total peninsula east shelf less than 1000