From active fault segmentation to risks of earthquake hazards and property and life losses—A case study from the Xianshuihe-Xiaojiang fault zone

• Published in: Science China. Earth sciences 2023-06, Vol.66 (6), p.1345-1364
• Main Authors: Cheng, Jia, Xu, Chong, Ma, Jian, Xu, Xiwei, Zhu, Pengyu
• Format: Article
• Language: English
• Subjects: Casualties; Deep learning; Disasters; Earth and Environmental Science; Earth Sciences; Earthquakes; Environmental risk; Fault lines; Fault zones; Geological faults; Geological hazards; Ground motion; Landslides; Landslides & mudslides; Mathematical analysis; Neural networks; Rescue operations; Residential areas; Residential buildings; Risk analysis; Rupturing; Segments; Seismic activity; Seismic hazard; Seismic response; Tectonics
• ISSN: 1674-7313; 1869-1897
• DOI: 10.1007/s11430-022-1076-y

Strong earthquakes generally rupture along active faults, and associated ground motion can cause earthquake disasters, property losses, and casualties from kilometers to tens of kilometers away. Therefore, one of the most effective ways to find earthquake’s dangerous parts of faults is to study the seismic hazards on fault segments. After that, we can also evaluate the probabilities of landslides hazard, property losses, and casualties. In this study, using fault slip rates and magnitude-frequency relationship as constraints, we calculated the earthquake occurrence rates for the segments along the Xianshuihe-Xiaojiang fault zone. We obtained 11 sites of single-segment or multi-segment rupturing risk. We also provided these potential events conditional probabilities in the next 30 years. For the 11 potential earthquakes, we calculated the property loss of residential buildings in the ground motion field. The most significant property loss is CNY 7.65 billion caused by the single-segment rupturing of the F19 segment on the Anninghe fault. We applied the deep learning neural network method in predicting the number of casualties for the potential earthquakes, showing that the most significant event is the multi-segment rupturing of the F29 and F30 segments on the Anninghe fault with the predicted death number of 279–317. We also evaluated the probabilities of earthquake landslides after the potential earthquakes. The results show that areas with intense compressional tectonic stress are highly unstable and prone to earthquake induced landslides, including the southern section of the Yuke fault, the southern section of the Xianshuihe fault, and the conjugated area between the southern section of the Daliangshan fault and the Lianfeng fault. These areas have a considerable number of earthquake landslides with probabilities >10%. The methodology and results will give us a new effective way of applying active fault data in earthquake hazard and risk analysis and provide a scientific path for earthquake prevention, disaster reduction, and emergency rescue preparation.