河流形态对天山内部斜向走滑断裂差异活动性的响应——以博罗科努断裂带为例

Multiple huge oblique strike-slip fault zones cuted obliquely interior Tienshan with a relatively strong activity since Quaternary. These faults have played a very important role during the evolution of tectonics in the Cenozoic Era. Also, it is a key point for the topographic changes, tectonic block movements and the seismic activities. But the lack of quantified descriptions of seismic geology and geodesy in this area makes it very limited to understand the adjustment role of those faults how to shorten along SN and how to Extend along WE within the Tienshan in the Quaternary. This study is focused on the 1000km-long Bolohkenu Fault zone which stretches over the North Tienshan. From the view of tectonic geomorphology, synergy of remote sensing images and DEM data with high spatial resolution reveals new data for active tectonism by tectonical geomorphology parameters along this fault zone. Cooperated with earthquake, geology, hydrology and geophysics data, we expect to mine deeply by dense quantitative parameters of deformation features on topography and fluvial geomorphology, to derive slip rates and geometry of different segments of the Bolohkenu Fault zone. Finally, deformation values of the horizontal and vertical direction of the fault zone will be analyzed together to inverse the tectonic activity of the fault zone and the relationship between deformation features and earthquakes. It will help us to explore the accomodation role of oblique strike-slip fault zones in the interior of Tian Shan played in the evolution of Tian Shan in the Quaternary.

天山内部斜向走滑断裂在天山新生代构造演化中发挥过重要作用，是调节天山地形地貌、构造板块运动及强震活动等的重要单元。但由于缺少定量化的地震地质和形变数据等关键资料，对这类断层在第四纪天山南北向缩短、东西向伸展变形过程中的调节作用仍认识有限。博罗科努断裂带规模宏大且主体在境内，是斜切整个北天山的北西向走滑构造带。本研究拟以该断裂带为目标断裂，采用构造地貌学研究方法，通过高精度、高分辨率遥感数据，获取断裂沿线密集的地形、河流形态的变形特征参数，并结合区域地震、地质、水文、地球物理等资料，确定该断裂带各段的几何学特征和运动速率，由此讨论其走滑、逆冲运动的时空分布特征，分析其调节的变形量的地震构造意义，探索陆内斜向走滑断裂在天山第四纪构造演化的调节作用。

从构造地貌学角度出发，以博罗科努断裂带中段-精河至乌鲁木齐段为研究目标，利用高精度光学遥感影像确定了断裂带的几何展布特征，利用DEM数据获取了定量化的地形地貌参数、断裂沿线河流的平面形态参数和纵剖面形态参数，反映断裂沿线河流形态的变形特征，并据此解释断裂带的构造运动特征；并结合前人的考证资料，分析了断裂带第四纪以来的走滑、逆冲位移量及相应的速率。.博罗科努断裂精河-乌鲁木齐段总长600余公里，走向近北西。断裂带的几何形态和运动学特征沿断裂走向均存在不同程度的变化。断裂的几何形态沿走向发生九次变化，平均变化值为17，值得后续开展深入研究。断裂北段走滑速率约为5.0 mm/a，中段约为7.3 mm/a，南段约为2.0 mm/a，垂直滑动速率约为0.36mm/a，与该区域历史地震震中位置分布和震级序列相吻合。.本项目产出的博罗科努断裂带遥感解译图（1:10万）、博尔塔拉蒙古自治州及邻区的断裂遥感解译图（1:10万），填补了博州及邻区目前缺乏较大比例尺完整遥感解译图的空白，客观、全面反映了博州及邻区地形地貌与断裂分布，以及不同活动性质、活动时代的断裂与地震的相关性，为博州地震应急、防震减灾工作提供了基础图件和科学依据。