ISSN 1003-8035 CN 11-2852/P

    云南鲁甸Ms6.5级地震震后滑坡的时空分异特征

    Spatio-temporal differentiation of landslide after the Ms6.5 Ludian earthquake in Yunnan Province

    • 摘要: 2014年8月3日云南鲁甸发生的Ms6.5级地震触发了大量滑坡,受强烈地震触发的滑坡震后恢复速度慢、恢复难度大且具有扩大复发的可能,会对道路、水体、生态环境造成长期影响,因此,探究其长时间时空分异具有必要性。以受地震影响的314 km2为研究区域,首先基于ENVI深度学习方法提取震后滑坡并编制其多时相数据清单,在此基础上,从滑坡时空分布特征、滑坡时空面积变化特征以及滑坡活动演化进行时空分异分析。结果表明:(1)地震后,滑坡数量和面积急剧增加,在随后的8 a时间内,总体呈现逐渐减少趋势,地震触发滑坡以面积小于0.01 km2的小型滑坡为主,集中分布于河谷两侧,同时距震中2000 m、地震烈度Ⅸ级范围内分布较为明显;(2)随时间推移,震后滑坡活动率总体表现为逐渐减弱趋势,截至2022年7月,地震触发滑坡只有6.08%的滑坡仍处于活动状态,表明地震对滑坡的影响已经逐渐减弱;(3)地震后滑坡的活动演化可以分为3个阶段:滑坡强活动期(2014年8月—2016年7月)、中等活动期(2016年8月—2021年8月)、弱活动期(2021年9月—2022年7月)。

       

      Abstract: A large number of landslides were triggered by the Ms6.5 magnitude earthquake that occurred in Ludian, Yunnan Province, on August 3, 2014. Landslides triggered by strong earthquakes exhibit slow post-earthquake recovery, high recovery difficulty, and tend to recur and expand, which can have long-term impacts on roads, water bodies, and ecological environments. Therefore, it is necessary to explore their long-time spatial and temporal variability. Taking the 314 km2 area affected by the earthquake as the study area, post-earthquake landslides were first extracted and a multi-temporal data list was compiled using the ENVI deep learning method. Based on this, the spatial-temporal differentiation analysis was carried out focusing on the spatio-temporal distribution characteristics of landslides, changes in spatio-temporal area, and the evolution of landslide activities. The results show that: (1) following the earthquake, the number and area of landslides increased dramatically, gradually decreasing over the subsequent 8 years. Earthquake-triggered landslides were primarily small-scale, with an area of less than 0.01 km2, concentrated on both sides of the river valley, and distributed more prominently within 2 000 meters from the epicenter and within seismic intensity Ⅸ; (2) over time, the post-earthquake landslide activity rate generally showed a gradual weakening trend, with only 6.08% of the earthquake-triggered landslides still active as of July 2022, indicating a gradual weakening of the earthquake's impact on landslides; (3) the activity evolution of post-earthquake landslides can be divided into three phases: the period of strong landslide activity (August 2014-July 2016), the period of moderate activity (August 2016-August 2021), and the period of weak activity (September 2021-July 2022).

       

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