Contrasting landslides distribution patterns and seismic rupture processes of 2014 Jinggu and Ludian earthquakes, China

Abstract

Abstract The destructiveness of earthquakes is often linked to their magnitude, but two similar-magnitude earthquakes in Yunnan, China in 2014 caused vastly different damage. The Ms 6.6 Jinggu earthquake triggered about 441 landslides, while the Ms 6.5 Ludian earthquake caused 10,559 landslides. In this paper, we focus on the correlations between distribution pattern of these landslides and seismic factors like seismogenic fault and epicenter. The results show that the landslides triggered by the Jinggu earthquake are mainly distributed along the blind northwest segment of the NW-striking Puwen fault, with more scattered and larger individual areas to the northwest of the epicenter, and more concentrated but smaller ones to the southeast. The distribution pattern of landslides triggered by the Ludian earthquake is predominantly controlled by the NW-striking Xiaohe-Baogunao fault. The landslides are concentrated within an area of 360 km2, with a greater number and larger size occurring in the southeastern section compared to the northwestern section. The distribution of coseismic landslides reveals key differences in rupture characteristics between the Jinggu and Ludian earthquakes. The Jinggu rupture mainly propagated deeper southeast, while the Ludian rupture in the southeast was shallower, reaching the surface. This was confirmed by aftershock data and field investigations. The larger rupture angle in the Ludian earthquake concentrated damage energy, causing more numerous and larger landslides. The contrasting rupture processes are a major factor behind the differing damage levels of these two similar-magnitude earthquakes.

Keywords

• Coseismic landslides
• Seismogenic fault
• Rupture process
• Jinggu earthquake
• Ludian earthquake