地质科技通报 (Jul 2021)

Spatio-temporal development characteristics of major geohazards in Sichuan Province around "5·12" Wenchuan earthquake

  • Guangchao Wen,
  • Linxue Su,
  • Hongbo Xie,
  • Hongqi Chen,
  • Zhaofeng Xu

DOI
https://doi.org/10.19509/j.cnki.dzkq.2021.0430
Journal volume & issue
Vol. 40, no. 4
pp. 143 – 152

Abstract

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The temporal and spatial development law of regional geohazards is the result of the joint action of internal and external geological forces, which are relatively stable within a large area. Therefore, the source, magnitude and occurrence time of earthquakes are the main factors affecting the temporal and spatial development law of regional geohazards. In order to study the impact of "5·12" Wenchuan earthquake on the spatial and temporal development of geohazards in Sichuan Province, based on the data of landslide, collapse, debris flow, earthquake and rainfall from 1998 to 2018, the spatial and temporal characteristics of major geohazards in Sichuan Province around the Wenchuan earthquake were analyzed by mathematical statistics and spatial analysis methods, The results show that: ① Activity in major disasters in Sichuan Province shows cycles, under normal circumstances, it presents a small cycle of about 3 years, after the earthquake geohazards increased year by year, to the peak of 4a, then decreased year by year; the impact is not obvious after 8 years; ② The relative intensity of major geohazards has little change after the earthquake, but the activity and intensity of geohazards are not corresponding before the earthquake. In the geomorphic division, the largest number of geohazards is in Sichuan Basin, and the most active is in Northwest Sichuan Plateau. Compared with that before the earthquake, the occurrence of geohazards in the quaternary system is higher than that in the hard rock area. The geohazards in the tectonic zones have obvious zoning characteristics. The earthquake intensity of the Yangtze quasi-platform is much greater than that of the Songpan-Ganzi geosynclinal fold system before and after the earthquake, but the disaster activity is obviously weaker than that of the Songpan-Ganzi geosynclinal fold system, and the basic structural units have similar characteristics.

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