Active faults and subsurface structure in Kinki Triangle Region, central Japan

本次科学研究的成果总结如下：对近畿三角地区的主要活动断层系统进行了研究。主要有六古-淡路断裂系、中央构造线断裂系、（和歌山、德岛地区）、京都盆地西缘、东缘断裂系、花入断裂系、铃鹿-登原断裂系等，开展了地貌调查、物探、钻探、探槽开挖等工作，收集了沿沿着断裂带的变形方式和地下构造信息，位移速率和断层活动年龄。特别是地质切片取样和连续分析显示了断层最近的活动。通过对能比平原、琵琶湖和大坂平原的沉积物样品进行<14>碳年代学和火山玻璃年代学分析，建立了晚第四纪沉积物年代学。Nojima Fault Prove项目的钻探样品表明了第四纪期间的垂直位移和沿断层的热活动沿着。通过对断层进行地震反射测量和重力测量，获得了地下构造信息，并根据中央构造线和有马-高月构造线的平移运动，验证了大坂沉积盆地形成的模型。在人工资料检验的基础上，提出了小断层分析的新方法，并将其应用于第四纪沉积物野外资料。

The result of this scientific research is summarized as below.Studies on main active fault systems in the Kinki Triangle region were carried out. There are Rokko-Awaji fault system, Median Tectonic Line fault .system (Wakayama and Tokushima Region), Western and Eastern margin fault system of Kyoto Basin, Hanaore fault system, and Suzuka -Toen fault system and so on. We have carried out geomorphological survey, geophysical prospecting, drilling, trench excavation, and collected the information on deformation mode and subsurface structure along the fault, displacement rate and age for fault activity. Especially, sampling by geoslicer and continuous analysis are shown most recent activities of the faults.Sediment samples from Nohbi Plain, Lake Biwa and Osaka Plain were analysed from the ^<14>C dating and volcanic glass chronology for establishing the chronology of Late Quaternary sediments.Drilling samples by Nojima Fault Prove project indicates vertical displacement during the Quaternary and thermal activity along the fault. Seismic reflection surveys and gravity measurement were carried out crossing the fault traces, and we obtained the information on subsurface structure.We checked the model on the formation of Osaka sedimentary basin on the basis of transcurrent movement of Median Tectonic Line and Arima-Takatsuki Tectonic Line. New method of minor faults analysis was also proposed on the basis of test by artificial data set, and applied to the field data of Quaternary sediments.