He Xiangli, Xu Chong, Qi Wenwen, Huang Yuandong
National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing, 100085, China.
Key Laboratory of Compound and Chained Natural Hazards Dynamics, Ministry of Emergency Management of China, Beijing, 100085, China.
Sci Rep. 2024 Nov 18;14(1):28470. doi: 10.1038/s41598-024-79682-8.
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 km, 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.
地震的破坏力通常与其震级相关，但2014年中国云南发生的两次震级相近的地震造成的破坏却大不相同。景谷6.6级地震引发了约441处山体滑坡，而鲁甸6.5级地震则造成了10559处山体滑坡。在本文中，我们重点关注这些山体滑坡的分布模式与诸如发震断层和震中等地震因素之间的相关性。结果表明，景谷地震引发的山体滑坡主要分布在北西向普洱断层的隐伏西北段，震中西北方向分布更为分散且单个区域面积较大，而东南方向则更为集中但面积较小。鲁甸地震引发的山体滑坡分布模式主要受北西向小河-包谷脑断层控制。山体滑坡集中在360千米的区域内，与西北段相比，东南段的数量更多且规模更大。同震山体滑坡的分布揭示了景谷地震和鲁甸地震在破裂特征上的关键差异。景谷地震的破裂主要向东南方向深部扩展，而鲁甸地震在东南方向的破裂较浅，直达地表。余震数据和实地调查证实了这一点。鲁甸地震中较大的破裂角度使破坏能量集中，导致了更多数量且规模更大的山体滑坡。这两次震级相近的地震破坏程度不同的主要原因在于其破裂过程的差异。
