Vol17 No.9: 2049-2067
【Title】Directional seismic response to the complex topography: A case study of 2013 Lushan Ms 7.0 earthquake
【Author】ZHAO Bo1,2*, WANG Yun-sheng2*, SU Li-jun1,3,4,5, LUO Yong-hong2, ZHANG Jing2
【Addresses】1 Key Laboratory of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2 State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; 3 CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China; 4 China-Pakistan Joint Research Center on Earth Sciences, Islamabad 30001, Pakistan; 5 University of Chinese Academy of Sciences, Beijing 100049, China
【Corresponding author】ZHAO Bo, WANG Yun-sheng
【Citation】Zhao B, Wang YS, Su LJ, et al. (2020) Directional seismic response to the complex topography: A case study of 2013 Lushan Ms 7.0 earthquake. Journal of Mountain Science 17(9). https://doi.org/10.1007/s11629-020-6038-y
【Abstract】Azimuthal variations in site response can provide a good insight into the site amplification and seismic conditions of geohazard occurrences. In this study, multiple directional site response methods, including D-Arias (Directional-Arias), D-SER (Directional- Shaking energy ratio), D-HVSR (Directional-Horizontal to vertical spectral ratio) and D-SSR (Directional – Standard spectral ratio), are adopted to analyse seismic data of the 2013 Lushan Ms 7.0 earthquake captured by the self-established Lengzhuguan (LZG) station which consists of the complex topography of isolated ridge, large mountain and some typical micro-reliefs. The results show that the isolated ridge could cause stronger site responses than the large mountain, and whose pronounced response direction is roughly perpendicular to its ridgeline. With the growth of elevation, the site resonant frequency decreases. The different micro-reliefs on the mountain cause different site responses, which present as protruding slope > linear slope. The site response mainly exists on the surficial layer of the mountain and shows that with the increase of the distance to mountain surface, the site response gets weaker, the site resonant frequency gets higher, and the pronounced response direction is perpendicular to its ridgeline.
【Keywords】Site response; Pronounced response direction; LZG station; Lushan Ms 7.0 earthquake