Late Pleistocene deformation and slip rate of the Median Tectonic Line Active fault system

中构造线（MTL）活动断裂带沿四国延伸约190公里，日本西南部。MTL是一条与菲律宾海板块沿南开海槽向欧亚板块下斜俯冲有关的弧形平行右旋走滑断裂。虽然MTL是日本西南海岸最重要的活动构造特征，但对其晚第四纪滑动速率、滑动矢量和断平面的估计却很少。我们绘制了偏置的晚更新世河流阶地表面，并使用碳14定年和温度年代学对其进行了定年。池田断层的累积偏移量（110±10m）和内缘年龄（15ka）产生的平均滑动速率为7.3±0.7mm/yr。利用摄影测量技术，采集了晚更新世阶地隆起的高分辨率数字高程模型（DEM），对Chichio断裂的累积断层滑动矢量进行了表征。在相似方向上，基于DEM的重建向量表明，垂直位移约为水平位移的十二分之一到十五分之一。用高角度北倾断裂面模型再现了Chichio断裂带上的河流阶地变形。

The Median Tectonic Line (MTL) active fault zone extends for about 190 km along in Shikoku, southwest Japan. The MTL is an arc-parallel, right-lateral strike-slip fault related to the oblique subduction of the Philippine Sea plate beneath the Eurasian plate along the Nankai trough. Though the MTL is the most significant active tectonic feature on shore in southwest Japan, its Late Quaternary slip rate, slip vector and fault plane have been estimated at very few locations. We mapped offset Late Pleistocene fluvial terrace surfaces and dated them using carbon 14 dating and tephrochronology. The cumulative offset (110±10m) and the age of the inner edge (15ka) on the Ikeda fault yields an average slip rate of 7.3±0.7mm/yr. High resolution digital elevation model (DEM) of a Late Pleistocene terrace riser were collected by using photogrammetry to characterize the cumulative fault slip vector across the Chichio fault. The reconstructed vectors based on DEM, to be similar direction are shown that the vertical displacement is about one twelfth to one fifteenth times as large as the horizontal displacement. The deformation of fluvial terrace across the Chichio fault is reproduced by a model with a high angle northward dipping fault plane.