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

Xin Wang, Susumu Kurahashi, Hao Wu, Hongjun Si, Qiang Ma, Ji Dang, Dongwang Tao, Jiwei Feng, Kojiro Irikura

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1185-1200
Number of pages16
JournalJournal of Seismology
Volume21
Issue number5
DOIs
Publication statusPublished - 2017 Sep 1

Keywords

  • 2014 Ludian earthquake
  • Aseismic capacity of buildings
  • Building collapse ratio
  • Seismogenic structure
  • Site effect
  • Underground velocity structures

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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