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白龙江流域地处青藏高原向黄土高原过渡的斜坡急剧变形带,是我国泥石流、滑坡灾害最为严重的地区之一,由于流域受多条断裂带的影响,内部相对构造活动强度存在差异,因此对该地区构造活动程度的研究显得尤为重要。本文基于SRTM3-DEM数据,利用GIS技术提取了白龙江流域33个子流域的面积高程积分(HI)、河流阶梯指数(SL)、流域盆地不对称度(AF)、流域形状指数(BS)、谷底宽度与谷肩高度比(VF)等5种地貌参数。然后对5种地貌参数进行分级,求取5种地貌参数分级值的算术平均值,作为评价研究区的构造活动程度(Iat),分为弱、中等、较强和强四类。研究结果表明,白龙江流域中上游地区构造活动程度为中等至强(Iat≤2),这与该地区受青藏高原隆升效应及断裂带走滑作用相一致。下游地区构造活动程度相对弱(Iat>2),地貌差异不明显,这与该地区主要断裂带第四纪以来活动性弱有关。研究结果与区域的地质背景相一致,该研究对利用地貌参数进行流域的活动构造量化分析具有借鉴意义。
The Bailongjiang River basin is located in the transition zone from the Qinghai-Xizang Plateau to the Loess Plateau. It is one of the areas where debris flow and landslide are the most serious in our country. Due to the influence of several fault zones in the basin, there are differences in the relative intensity of relative tectonic activity. The study of the extent of regional tectonic activity is particularly important. Based on the SRTM3-DEM data, the elevations of HI, river step index (SL), basin basin asymmetry (AF), basin shape index (BS), valley bottom width And shoulder height ratio (VF) and other five kinds of topographic parameters. Then the five kinds of landform parameters are graded, and the arithmetic average of the five kinds of landform parameter grading values is obtained, which is used to evaluate the tectonic activity (Iat) of the study area, and divided into weak, moderate, strong and strong four categories. The results show that the tectonic activity in the middle and upper reaches of Bailongjiang River Basin is moderate to strong (Iat≤2), which is consistent with the uplift effect of the Tibetan Plateau and the slip-out of the fault zone in this area. The tectonic activity of the lower reaches is relatively weak (Iat> 2), and the difference of landform is not obvious, which is related to the weak activity since the Quaternary of the main fault zone in the area. The research results are consistent with the regional geological background. This study is of reference significance for the quantitative analysis of the active tectonics in the basin using the geomorphic parameters.