孙鹏, 胡磊, 胡玉乾, 张强, 李虎, 湛睿. 横断山区汶川县滑坡泥石流降雨致灾阈值研究[J]. 北京师范大学学报(自然科学版), 2023, 59(2): 187-195. DOI: 10.12202/j.0476-0301.2021302
引用本文: 孙鹏, 胡磊, 胡玉乾, 张强, 李虎, 湛睿. 横断山区汶川县滑坡泥石流降雨致灾阈值研究[J]. 北京师范大学学报(自然科学版), 2023, 59(2): 187-195. DOI: 10.12202/j.0476-0301.2021302
SUN Peng, HU Lei, HU Yuqian, ZHANG Qiang, LI Hu, ZHAN Rui. On disaster threshold of landslide and debris flow rainfall in Wenchuan County[J]. Journal of Beijing Normal University(Natural Science), 2023, 59(2): 187-195. DOI: 10.12202/j.0476-0301.2021302
Citation: SUN Peng, HU Lei, HU Yuqian, ZHANG Qiang, LI Hu, ZHAN Rui. On disaster threshold of landslide and debris flow rainfall in Wenchuan County[J]. Journal of Beijing Normal University(Natural Science), 2023, 59(2): 187-195. DOI: 10.12202/j.0476-0301.2021302

横断山区汶川县滑坡泥石流降雨致灾阈值研究

On disaster threshold of landslide and debris flow rainfall in Wenchuan County

  • 摘要: 基于2001—2020年GPM L3降水数据和第二次青藏科考所获取的2018年汶川县汛期滑坡泥石流灾害隐患点目录,从强度、相对性、绝对性和持续性方面遴选11个极端降水指标,揭示汶川县极端降水时空演变规律;通过构建累积降雨量-降雨时间关系阈值(E-D)模型、优化雨场分割法、量化汶川县降雨型滑坡泥石流样本降雨阈值,分级预测2001—2020 年降雨型滑坡泥石流灾害隐患点的危险等级.研究结果表明:1)极端降水指标在汶川县大部分乡镇点位的趋势变化不显著,大多数指标呈现北低南高、西低东高的空间分布特征.极端降水的相对性指标、强度性指标以及部分持续性指标在空间分布上具有一致性,高值区主要分布在汶川县东部和南部地区,其发生由极端降水诱发的滑坡泥石流地质灾害事件的可能较大.2)汶川县降雨型滑坡E-D 阈值曲线为E = 41.69·D0.84(3≤D≤6),降雨型泥石流E-D 阈值曲线为E = 81.28·D0.36 (3≤D≤23) .3)汶川县“易发生”的降雨型滑坡隐患点占比46.2%,集中位于水磨镇北部、漩口镇东部、草坡乡东南部、绵虒镇中南部、耿达镇东南部、映秀镇东部以及卧龙镇东北部,“易发生”的降雨型泥石流隐患点占比13.84%,集中位于草坡乡东南部和银杏乡西部,该些区域未来需重点关注其降雨预警。“易发生”“较易发生”的滑坡泥石流隐患点的分布与极端降水的强度性、相对性和部分持续性指标的高值分布具有高度的吻合性.本研究可为汶川县极端降雨诱发滑坡泥石流灾害事件的防灾减灾提供精细化预报预警.

     

    Abstract: Data of GPM L3 precipitation from 2001-2020, catalogue of hidden danger points of landslide and debris flow disasters in flood season in Wenchuan County in 2018 from the second Qinghai-Tibet scientific expedition, were used to select 11 extreme precipitation indexes taking into account of intensity, relativity, absoluteness and sustainability, to reveal the spatiotemporal evolution law of extreme precipitation in Wenchuan County.Cumulative rainfall-duration relationship threshold (E-D) model was constructed, rain field segmentation method was optimized, rainfall threshold of rainfall-type landslides and debris flows in Wenchuan County was quantified, risk grade of hidden danger points of rainfall-type landslides and debris flows were evaluated for period 2001-2020.The change of extreme precipitation index in most villages and towns in Wenchuan County was found not obvious, most indexes showed spatial distribution of low in the north, high in the south, low in the west and high in the east.The relativity index, intensity index and partial persistence index of extreme precipitation were very similar in spatial distribution.The precipitation in the eastern and southern areas of Wenchuan County showed high intensity, relativity and persistence, likelihood for geological disasters due to extreme precipitation was high.The E-D threshold curves of rainfall-type landslides and debris flows in Wenchuan County were: E = 41.69·D0.84(3≤D≤6) and E = 81.28·D0.36(3≤D≤23), respectively.The “easy-to-happen” hidden danger points of rainfall-type landslides in Wenchuan County accounted for 46.2%, being concentrated in the north of Shuimo Town, the east of Xuankou Town, the southeast of Caopo Township, the south-central of Mianqi Town, the southeast of Gengda Town, the east of Yingxiu Town and the northeast of Wolong Town.The “easy-to-happen” hidden danger points of rainfall-type landslides accounted for 13.84%, being concentrated in the southeast of Caopo Township and the west of Yinxing Township.The distribution of “easy to occur” and “relatively easy to occur” hidden danger points of landslides and debris flows was highly consistent with the intensity, relativity and partial sustainability indexes of extreme precipitation.The present work provides detailed forecast and early warning for disaster prevention and mitigation of landslides and debris flows caused by extreme rainfall events in Wenchuan County.

     

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