摘要
强烈的山区地震往往会引发大量同震滑坡,对当地植被覆盖和生长造成直接破坏。作为表现滑坡活动强度的重要指标,同震滑坡体表面的植被恢复情况对评估震后地质灾害的活动情况具有重要意义。然而,受观测资料所限,当前对于震区植被恢复进程的研究多为小尺度范围,而对大区域内植被演化机制以及植被与地质灾害活动性的关系认识不足。因此,采用多时相、长时序(2000—2020年)的高精度遥感影像对汶川地震强震区大范围内的植被恢复过程进行研究,计算得到不同时期植被恢复率,以此探究大范围内植被恢复的普适性规律,同时分析植被恢复与滑坡活动强度变化的关系。研究发现:截至2020年,71.34%区域的同震滑坡表面植被已处于恢复程度较好阶段;高活动强度、中活动强度、低活动强度和基本稳定的滑坡面积比分别为17.6%、12.4%、17.7%和52.3%。同震滑坡地表恢复趋势表明,汶川震区植被预计在震后约17 a恢复至震前平均水平。然而,植被恢复过程和滑坡活动性的变化往往受多种因素的综合影响。虽然滑坡地表植被恢复在一定程度上反映了地震后滑坡活动性的下降,但地震对滑坡活动性的影响将比地表植被恢复到震前水平所持续的时间更长。参考前人研究成果,本研究认为震后滑坡活动将持续25 a或更长时间。研究成果可为汶川震区震后地质灾害评估、防治工作提供参考。
A great mountain seismic often triggers a large number of co-seismic landslides,causing direct damage to local vegetation cover and growth.As an important indicator of landslide activity intensity,the vegetation recovery is of great significance for the activity of post-earthquake geo-hazards.However,due to the limitation of observational data,the current research on vegetation restoration process in earthquake areas is mostly on a small scale.In addition,there is insufficient understanding of the vegetation evolution mechanism in a large area and the relationship between vegetation and the activity of geological disasters.Therefore,this paper uses multi-temporal and long-time series(2000−2020)high-precision remote sensing images to study the vegetation restoration process in the Wenchuan earthquake area.By calculating vegetation recovery rates in different periods,we explore the universal law of vegetation restoration in a large range,and analyze the relationship between vegetation restoration and the change of landslide activity intensity.The results show that by 2020,71.34%of the landslide area in the earthquake area has been better restored.The proportions of highly active,moderately active,low active and basically stable landslides are 17.6%,12.4%,17.7%and 52.3%,respectively.The surface recovery trend of co-seismic landslide indicates that the vegetation in the Wenchuan earthquake area is expected to recover to the pre-earthquake average level about 17 years after the earthquake.However,the process of vegetation recovery and changes in landslide activity are often subject to the combined effects of multiple factors.Although the vegetation recovery of landslide surface reflects the decline of landslide activity after the earthquake to some extent,the effects of the earthquake on landslide activity will last longer than the recovery of surface vegetation to the pre-earthquake level.Referring to the results of previous studies,this paper suggests that the post-earthquake landslide activity will last 25 years or more.The conclusion can provide reference for the assessment and prevention of post earthquake geological disasters in Wenchuan earthquake area.
作者
李明威
熊江
陈明
唐川
LI Mingwei;XIONG Jiang;CHEN Ming;TANG Chuan(Institute of Geophysical and Geochemical Exploration,CAGS,Langfang,Hebei 065000,China;National Research Center of Geoexploration Technology,Langfang,Hebei 065000,China;Institute of Mountain Hazards and Environment,CAS,Chengdu,Sichuan 610041,China;State Key Laboratory of Geohazard Prevention and Geo-environment Protection(Chengdu University of Technology),Chengdu,Sichuan 610059,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2023年第3期182-192,共11页
Hydrogeology & Engineering Geology
基金
国家重点研发计划项目(2017YFC1501004)
中国地质科学院地球物理地球化学勘查研究所基本科研业务费项目(AS2022J02)。
关键词
汶川地震
同震滑坡
植被恢复
滑坡活动性
Wenchuan earthquake
co-seismic landslide
vegetation restoration
landslide activity
