Database and spatial distribution of landslides triggered by the Lushan, China Mw 6.6 earthquake of 20 April 2013
Database and spatial distribution of landslides triggered by the Lushan, China Mw 6.6 earthquake of 20 April 2013
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2013年4月20日中国芦山6.6级地震引发的滑坡数据库和空间分布
DOI：
10.1016/j.geomorph.2015.07.002
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发表时间：
2015
期刊：
影响因子：
3.9
通讯作者：
J. Bruce H. Shyu
中科院分区：
文献类型：
--
作者：
许冲;Xiwei Xu;J. Bruce H. Shyu
2013 年 4 月 20 日，中国四川省芦山县（北纬 30.3°，东经 103°）发生了 6.6 级地震（7.0 级），距离 2008 年汶川 7.9 级地震西南仅 85 公里。芦山地震引发了大量不同类型的滑坡，包括高度破坏的浅层滑坡和落石、深部滑坡和大规模岩崩。收集震后高分辨率航空照片和卫星图像以及一系列震前高分辨率卫星图像，构建详细、准确、客观、完整的同震滑坡数据库/清单，并通过选定地区的现场调查进行验证。根据部分覆盖受影响地区的航空照片（0.2 或 0.6 m 分辨率）和震前卫星图像，识别并绘制了 14,580 个同震山体滑坡。在那些没有震后航空照片覆盖的地区，我们根据震后卫星图像（分辨率为5 m的Rapideye图像和ZY-3图像，包括分辨率为2.1 m的全色图像和分辨率为5.8 m的多光谱图像）和震前卫星图像绘制了7,948个同震滑坡。同震滑坡共22528处，水平投影面积18.88平方公里，估算总体积41.56×106立方米，分布在约5400平方公里的近椭圆形区域。对 15,546 个面积≥ 100 m2 的滑坡进行了分析，分析了同震滑坡丰度与地形、地质和地震因素之间的相关性。广义均质岩性组合中区域坡度与滑坡丰度之间的散点图显示它们之间不存在明显的关系，这对前人研究的结论提出了挑战。将芦山地震引发的滑坡与逆断层和/或逆冲断层上的其他事件（例如1999年集集地震和2008年汶川地震）相结合，我们发现同震滑坡往往发生在两个或多个叠瓦状逆断层和/或逆冲断层包围的区域，而不仅仅是沿着发震断层。与其他类似震级的地震相比，芦山地震具有更高的引发滑坡的能力，这可能是由于长期构造活动造成的地势陡峭崎岖和岩性破碎、密理所致。盲目的逆发震断层可能也是另一个重要因素。基于2008年汶川、2010年海地、2010年玉树和2013年芦山地震等近期几次大地震的详细同震滑坡库存图和数据库，我们建议需要更新地震震级与同震滑坡之间的经验相关性。
On 20 April 2013, an earthquake with Mw 6.6 (Ms 7.0) hit Lushan County, Sichuan Province of China (30.3°N, 103°E), only 85 km southwest of the 2008 Wenchuan Mw 7.9 event. The Lushan shock triggered a large number of landslides with various types, including highly disrupted shallow slides and rock falls, deep-seated landslides and large-scale rock avalanches. Post-earthquake high resolution aerial photographs and satellite images, as well as a series of pre-earthquake high resolution satellite images were collected to construct a detailed, accurate, objective, and complete coseismic landslide database/inventory, which was validated by field investigation in selected areas. Based on the aerial photographs (0.2 or 0.6 m resolution) that partly cover the affected area and pre-earthquake satellite images, 14,580 coseismic landslides were recognized and mapped. In those areas without post-earthquake aerial photographs coverage, we mapped 7,948 more coseismic landslides based on post-earthquake satellite images (Rapideye images with 5 m resolution and ZY-3 images including panchromatic images with 2.1 m resolution and multi-spectral images with 5.8 m resolution) and pre-earthquake satellite images. The 22,528 coseismic landslides, with a horizontal projection area of 18.88 km2and an estimated total volume of 41.56 × 106m3, were distributed in a nearly elliptic area of about 5,400 km2. Correlations between coseismic landslide abundances and topographic, geologic, and seismic factors were analyzed on 15,546 landslides of area ≥ 100 m2. Scatter plots between regional slope angle and landslide abundances in generalized homogeneous lithology combinations show no obvious relationship is present between them, which challenges the conclusions of previous studies. Combining the Lushan earthquake-triggered landslides with other events on reverse and/or thrust faults such as the 1999 Chi-Chi and 2008 Wenchuan shocks, we found that coseismic landslides tend to occur in areas enveloped by two or more imbricated reverse and/or thrust faults, rather than only along the seismogenic fault. The Lushan event shows a higher ability of triggering landslides compared with other earthquakes of similar magnitudes, which is likely due to the steep and rugged topography and fractured and densely jointed lithology resulted from long-term tectonic activity. The blind reverse seismogenic fault is likely also another significant factor. Based on detailed coseismic landslide inventory maps and databases of several recent major earthquakes such as the 2008 Wenchuan, 2010 Haiti, 2010 Yushu, and 2013 Lushan temblors, we suggest that the empirical correlations between earthquake magnitude and coseismic landslides need to be updated.