Integrated seismic experiments with active and passive sources for revealing the crustal structure of the collision / subduction transition zone on the northwestern border of the Izu arc

从藤川-加古断裂系统到伊藤川-静冈构造线的综合地震实验揭示了地壳结构及其活动如下：藤川-卡古断裂系统是一个向西倾的逆断裂系统，其位置非常接近菲律宾海板块的上表面。2. 断裂系东缘的大宫断裂不是一个高角度的正断层，而是一个近地表的低角度逆冲断层。3. 如果采用目前仅基于垂直位移率的方法，则对断层系统的活动性评价过低。4. 由于沿断层系统的横向位移不能被忽略，因此三维调查对于更精确的评估是必要的。5. 上新世末期，伊藤川—静冈构造线及其伴生断裂的活动明显减弱。早更新世以来，主导断裂活动向东转移至藤川-卡古断裂体系。

Integrated seismic experiments from the Fujikawa-kako fault system to the Itoigawa-Shizuoka tectonic line have revealed crustal structures and their activities as follows.1. The Fujikawa-kako fault system, a W-dipping reverse fault system, is traceable downward very close to the upper surface of the Philippine Sea plate. 2. The Omiya fault, the eastern margin of the fault system, is not a high-angle normal fault, but a low-angle thrust near the surface. 3. The activities of the fault system must be evaluated too low, if the present method based only on the vertical displacement rate is adopted. 4. 3-D investigations are necessary for more precise evaluations because lateral displacements cannot be ignored along the fault system. 5. The activities of the Itoigawa-Shizuoka tectonic line and its associated faults diminished considerably by the end of Pliocene. Since early Pleistocene, dominant fault activities have shifted eastward into the Fujikawa-kako fault system.