Seismic hazard prediction using multispectral amplification maps in a complex topographic area: A case study of Qiaozhuang town, Sichuan Province, Southwest China

Abstract

Earthquakes can cause widely distributed slope failures and damage in mountainous areas. The accurate prediction of ground motions in mountainous areas is essential for managing the seismic risk of urban cities near mountains but is restricted primarily by complex seismic site amplification effects in areas of uneven terrain. This study selected Qiaozhuang town located in the Qingchuan-Pingwu fault zone, Southwest China, as a case study. A simulator for mapped seismic responses using a hybrid model (SiSeRHMap) was applied to compute the multispectral seismic topographic amplification maps at the three slope units surrounding Qiaozhuang town (Weigan hill, Mt. Dong, and Mt. Shizi). Post-earthquake damage survey maps, 1D seismic site response spectral ratios, and H/V spectral ratios of earthquake data were used to validate the computed seismic site amplification factors and resonance frequencies. The results suggest that strong topographic amplification effects usually occur at distinct slope locations, such as hilltops, convex slope positions, upslope, and narrow ridges. The computed topographic amplification factors in the study area reached up to 2.4 at upslope or hilltops, and the resonance frequencies were between 3 and 10 Hz. Topographic effects can be as important as stratigraphic effects when assessing seismic amplification effects in the study area. We conclude that both topographic and stratigraphic effects should be considered in the comprehensive seismic hazard assessment of the study area or other similar mountain towns.

Agriculture Risks and Opportunities in a Climate-Vulnerable Watershed in Northeastern Taiwan—The Opinions of Leisure Agriculture Operators

“…The inventories of farm risks and opportunities to climate change in the literature [49,64] were screened by the local reality and opinions of the whole population of leisure agriculture operators as stakeholders. Compared with the literature [49,64], local risks and corresponding adaptations vary due to the locality of varying climatic zones, differing altitude, and terrain characteristics [22]. Although the farm risks and adaptation measures in the LRW differed, this study yielded three similar results.…”

“…In addition to climate factors, altitude and terrain characteristics are often key factors in local climate hazards and corresponding adaptations [22]. Zagaria et al [23] highlighted the importance and necessity of adaptation and transformation.…”

A Computer-Aided Algorithm Combined with an Integrated Downhole Method to Improve Shear Wave Detection and Damping Ratio Assessment: Theory and Preliminary Results

“…In an earthquake event, the propagation of seismic waves in cover deposits induces site effects which are physically modeled as complex damped-oscillator systems. These natural systems can change the amplitude and frequency of the input motion coming from the stiffer deep rock mainly about the shear wave velocity and damping ratio of ground materials composing the subsoil (e.g., [26][27][28][29][30][31][32]). Within this framework, the in-hole seismic methods provide more accurate and direct measurements of the body-wave velocities than the surface seismic methods.…”