The Philippine Sea Plate has an extremely special tectonic background. As an oceanic plate,it is almost entirely surrounded by subduction zones with complex internal tectonic features. On the basis of enormous publish...The Philippine Sea Plate has an extremely special tectonic background. As an oceanic plate,it is almost entirely surrounded by subduction zones with complex internal tectonic features. On the basis of enormous published literature,this paper offers a comprehensive overview of the tectonic and evolution history of the Philippine Basin and the Kyushu-Palau Ridge（KPR） in the Philippine Sea Plate,and discusses the geological features of KPR. Referring to relevant definitions of various ＂ridges＂ stipulated in United Nations Convention on the Law of the Sea,so the KPR is believed to be a remnant arc formed during the opening of the Parece Vela and Shikoku Basins in the Philippine Sea Plate. It is a submarine ridge on oceanic plate rather than a submarine elevation. And thus,it is not a natural component of the Japan continental margin.展开更多
Kanagawa Prefecture, Japan, is just located on the tectonic plate boundary between the Philippines Sea Plate and the North American Plate. This tectonic plate boundary is called Sagami Trough and located in Sagami Bay...Kanagawa Prefecture, Japan, is just located on the tectonic plate boundary between the Philippines Sea Plate and the North American Plate. This tectonic plate boundary is called Sagami Trough and located in Sagami Bay. The 1923 Great Kanto Earthquake （Mj7.9） occurred on this plate boundary sub-ducting from Sagami Trough, the damage due to this earthquake was so huge in Kanaawa Pref., especially, along the big river, called Sagami River, located at the middle part of Kanagawa Pref. which was mostly seriously damaged. It is caused by the soft soil deposit along the Sagami River. So, in this study, we first confirmed the results of single point microtrcemor observation of about 980 points in the target area, and at this time, we tried to investigate the surface soil structure by using the miniature array microtrcemor observation, and aimed to estimate the overall ground structure of Sagami Plain. The ground structure of Sagami plains is complex, but the northern part of the plain is relatively simple and soft soil layer is shallow and stable. But the plains of the southern part, especially the west side of the Sagami River were found to be fairly soft ground. Following above, the surface soil structure in north-south direction is very clearly changed depending on the distance from the sea coast. A changing gap on the basement is very quickly appeared about 10 km far from the coast. And also, we calculated the average Vs of the surface ground and confirmed the consistency with the current ground state while confirming the historical change and the topography situation.展开更多
基金The National Basic Research Program (973) of China under contract No. 2007CB41170301Special Fund for Marine Scientific Research in the Public Interest under contract Nos 200805078, 201205003 and 201205037
文摘The Philippine Sea Plate has an extremely special tectonic background. As an oceanic plate,it is almost entirely surrounded by subduction zones with complex internal tectonic features. On the basis of enormous published literature,this paper offers a comprehensive overview of the tectonic and evolution history of the Philippine Basin and the Kyushu-Palau Ridge（KPR） in the Philippine Sea Plate,and discusses the geological features of KPR. Referring to relevant definitions of various ＂ridges＂ stipulated in United Nations Convention on the Law of the Sea,so the KPR is believed to be a remnant arc formed during the opening of the Parece Vela and Shikoku Basins in the Philippine Sea Plate. It is a submarine ridge on oceanic plate rather than a submarine elevation. And thus,it is not a natural component of the Japan continental margin.
文摘Kanagawa Prefecture, Japan, is just located on the tectonic plate boundary between the Philippines Sea Plate and the North American Plate. This tectonic plate boundary is called Sagami Trough and located in Sagami Bay. The 1923 Great Kanto Earthquake （Mj7.9） occurred on this plate boundary sub-ducting from Sagami Trough, the damage due to this earthquake was so huge in Kanaawa Pref., especially, along the big river, called Sagami River, located at the middle part of Kanagawa Pref. which was mostly seriously damaged. It is caused by the soft soil deposit along the Sagami River. So, in this study, we first confirmed the results of single point microtrcemor observation of about 980 points in the target area, and at this time, we tried to investigate the surface soil structure by using the miniature array microtrcemor observation, and aimed to estimate the overall ground structure of Sagami Plain. The ground structure of Sagami plains is complex, but the northern part of the plain is relatively simple and soft soil layer is shallow and stable. But the plains of the southern part, especially the west side of the Sagami River were found to be fairly soft ground. Following above, the surface soil structure in north-south direction is very clearly changed depending on the distance from the sea coast. A changing gap on the basement is very quickly appeared about 10 km far from the coast. And also, we calculated the average Vs of the surface ground and confirmed the consistency with the current ground state while confirming the historical change and the topography situation.
