| 汶川震区北川县泥石流流域崩滑体时空演变特征 |
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| 引用本文： | 李明威,唐川,陈明,史青云.汶川震区北川县泥石流流域崩滑体时空演变特征[J].水文地质工程地质,2020,47(3):182-190. |
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| 作者姓名： | 李明威 唐川 陈明 史青云 |
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| 基金项目： | 国家重点研发计划项目(2017YFC1501004);国家自然科学基金项目(41672299) |
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| 摘 要： | 2008年5月12日的汶川大地震引发了大规模同震山体滑坡，随后的强降雨又引发新的山体滑坡,滑坡形成的松散固体物质成为后续泥石流灾害的主要物质来源。为探究强震区泥石流流域崩滑体时空演变特征，文章以北川县魏家沟等8条泥石流流域为例，选取8期遥感影像（2008年震后、“9.24”泥石流发生后、2010年、2011年、2013年、2014年、2015年、2016年），分别解译崩滑体，统计其空间分布特征。此外，利用归一化植被指数（NDVI）计算研究区内植被覆盖度（VFC）及植被覆盖度恢复率（VCRR）。结果表明:研究区内崩滑体发育面积在强降雨作用后达到峰值，随后呈稳定恢复状态，面积逐年减小。崩滑体在高程900~1 100 m范围、坡度30°~45°范围、坡向90°~135°范围、距沟道150 m范围内发育面积最大。流域内植被覆盖度在2008年“9.24”泥石流灾害后最低，随后呈稳定恢复。自震后到2010年的时期内，植被覆盖度恢复率中等以下区域较多，植被恢复程度较低。2011年之后，流域内大多区域处于植被覆盖度恢复率中等以上等级，植被恢复程度较高。到2016年，研究区植被覆盖度已恢复至较高水平。研究表明:除地层岩性、微地貌等因素影响外，植被对泥石流活动性具有一定的抑制作用。
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| 关 键 词： | 遥感 崩滑体 时空演变 泥石流 植被恢复 汶川震区 |
| 收稿时间： | 2019-09-02 |
Spatio -temporal evolution characteristics of landslides in debris flow catchment in Beichuan County in the Wenchuan earthquake zone |
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| Abstract: | The Wenchuan Earthquake on May 12, 2008 triggered a large -scale co -seismic landslide, and the subsequent heavy rainfall prompted the formation of a new landslide. These loose solid materials became the main material source for subsequent debris flow disasters, which seriously threaten people’s lives and property security. In order to explore the spatio -temporal evolution characteristics of the landslide in the debris flow catchment in the strong earthquake area, this paper takes the eight catchments dominated by the Weijiagou in Beichuan County as an example, and selects eight remote sensing images (after the earthquake in 2008, after the “9.24”debris flow, and in 2010, 2011, 2013, 2014, 2015 and 2016), to respectively interpret the landslides, and calculate their spatial distribution characteristics. We also calculated the vegetation coverage (VFC) and vegetation coverage recovery rate (VCRR) in the study area using the normalized vegetation index (NDVI). The research results show that the development area of the landslide in the study area reaches a peak after the heavy rainfall, and then it returns to a stable state, and the area decreases year by year. The collapse body has the largest development area in the range of 900-1 100 m in elevation, 30°-45° in slope, 90°-135° in the slope direction and 150 m in the channel. The vegetation coverage in the catchment was the lowest after the “9.24”debris flow disaster, and then recovered stably. In the period from the earthquake to 2010, the vegetation coverage recovery rate is more than moderate, and the vegetation restoration degree was low. After 2011, most areas in the catchments were at a medium or higher level of vegetation coverage recovery rate, and the degree of vegetation restoration was higher. By 2016, the vegetation coverage of the study area has returned to a high level of 0.86.This study also shows that vegetation has a certain inhibitory effect on debris flow activity. |
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