Building damage concentrated in Longtoushan town during the 2014 Ms. 6.5 Ludian earthquake, Yunnan, China: examination of cause and implications based on ground motion and vulnerability analyses
| Autor: | Dongwang Tao, Hao Wu, Kojiro Irikura, Ji Dang, Jiwei Feng, Susumu Kurahashi, Xin Wang, Hongjun Si, Qiang Ma |
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| Rok vydání: | 2017 |
| Předmět: |
geography
geography.geographical_feature_category 010504 meteorology & atmospheric sciences business.industry Bedrock Ambient noise level Magnitude (mathematics) Masonry Fault (geology) 010502 geochemistry & geophysics 01 natural sciences Geophysics Terrace (geology) Geochemistry and Petrology Pluvial Structural geology business Seismology Geology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Seismology. 21:1185-1200 |
| ISSN: | 1573-157X 1383-4649 |
| Popis: | Though the 2014 Ludian Earthquake had only a moderate magnitude (Ms 6.5), high-level ground motions of almost 1g occurred at Longtoushan Town (seismic station 53LLT), which located near the intersection of a conjugate-shaped seismogenic fault. The building damages on the pluvial fan and the river terrace at Longtoushan was clearly different. In order to examine the generation of the large acceleration at 53LLT, the focal mechanisms and the rupture processes of the conjugate-shaped seismogenic fault were determined. We found that there were two continuous impulsive waves in the records of 53LLT that were generated from two different faults, the Baogunao fault and the Xiaohe fault, respectively. Site effects on the pluvial fan and the river terrace at Longtoushan Town and their relations to different building damages were examined. We found that the predominant period at the pluvial fan was about 0.25 s, close to the fundamental natural period of multi-story confined masonry buildings. Ground motions on the pluvial fan and the river terrace were simulated through convolving synthesized bedrock motions with the transfer functions, which were analyzed using the one-dimensional underground velocity structures identified from H/V spectral ratios of ambient noise. Building collapse ratios (CRs) are estimated based on the vulnerability function of the 2008 Wenchuan Earthquake and are compared with the observed values. We found that the observed building CRs on the pluvial fan are much higher than the estimated values. High-level ground shaking that is far beyond the design level was a reason for serious building damage. |
| Databáze: | OpenAIRE |
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