基于树木年轮重建密云小西天流域泥石流事件  

Debris flow event in Xiaoxitian watershed of Miyun based on tree ring reconstruction

作　　者：王志兰 马超[1] 吴佳亮 苗绿 路璐[2] WANG Zhilan;MA Chao;WU Jialiang;MIAO Lv;LU Lu(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Beijing Institute of Geology,Beijing 100120,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]北京市地质研究所,北京100120

出　　处：《自然灾害学报》2022年第5期183-192,共10页Journal of Natural Disasters

基　　金：北京市科技计划课题项目(Z191100001419015);国家自然科学基金项目(41702369);北京林业大学储备项目(2018BLCB03)。

摘　　要：树轮地貌法为充分掌握偏远山区泥石流灾害史提供了一种非常有效的技术手段。文中基于树轮地貌法,在已知部分灾害年基础上,对北京市密云区小西天沟泥石流灾害史以及空间分布模式进行重建,并讨论分析树轮生长对泥石流活动响应的滞后效应。结果表明:1968-2018年间,共有17个泥石流事件,最远的可追溯到1977年,最近一次为2015年。重建的响应指数大小表明:1989和1991年大规模强度的泥石流事件带走了源区大量的松散固体物质,接下来很长一段时间的泥石流灾害强度都相对较小。泥石流平均5年期频率为1.7,20世纪末和21世纪初活动频率逐渐增大。基于重建事件和扰动木空间位置,确定了泥石流的2种基本空间分布模式:泥石流至少在3个分段区域内同时暴发的全流域型事件和仅在2个及以下分段区域内同时活动的局部型事件。研究显示不同树龄树轮生长对泥石流活动造成的生长抑制的滞后效应敏感性存在差异,与幼龄树木相比,成熟或老龄树的生长抑制滞后效应显著,但生长释放无明显差异。Dendrogeomorphology provides an accurate method for reconstructing debris flow events in remote watershed.In this work,the history and spatial distribution pattern of debris flows in Xiaoxitian watershed,Miyun District,Beijing were reconstructed.The delaying effect of growth disturbance after debris flow event was analyzed.The results revealed that there were 17 debris flow events during 1968 and 2018,with last event in 1977 and recent event in 2015.The event response index showed that the subsequent debris flows after 1989 and 1991 were small scale.The average 5-year frequency of debris flow event was 1.7,and debris flow event increased since the end of the 20th century and till the beginning of the 21st century.Based on the reconstructed events and the spatial location of the disturbed wood,two basic spatial distribution patterns of debris flow were determined:the large-scale events in three sub-areas and the small-scale event in two or less sub-areas.Compared with young trees,the delaying effect of growth suppression of mature or old trees is significant,but there is no significant difference in growth release.

关 键 词：小西天沟 泥石流 伤疤 滞后效应 生长抑制 

分 类 号：P642[天文地球—工程地质学] X43[天文地球—地质矿产勘探]