Landslides triggered by the 3 August 2014 Ludian earthquake in China: geological properties, geomorphologic characteristics and spatial distribution analysis

摘要

On 3 August 2014, an earthquake of Mw 6.5 happened in Ludian County, Yunnan Province, China. This earthquake triggered hundreds of landslides of various types, dominated by shallow slides, deep-seated slides, rock falls, debris flow and unstable slopes. Using field investigations and remote sensing images, 413 landslides triggered by the Ludian earthquake were statistically analyzed. Statistical analyses show that most of the landslides are shallow slides with a small volume. Most of these landslides are concentrated near the epicentre with distances ranging from 6?￠????12 km, especially at the upper slope along the river valley. The number of landslides increased with increasing distance from the epicentre (0?￠????9 km) and then decreased with increasing distance from the epicentre (>9 km). The landslides decreased in density with increasing distance from the fault rupture. More than 70% of the landslides occurred on the right side of the Xiyuhe-Zhaotong fault, when viewed from Southwest (SW) to Northeast (NE). Slope aspect and gradient had a substantial influence on the landslide distribution and landslide density increased with increasing slope gradient. Approximately, 65% of the landslides happened at the back slope with respect to the earthquake epicentre.