Development and distribution of geohazards triggered by the 5.12 Wenchuan Earthquake in China |
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Authors: | RunQiu Huang WeiLe Li |
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Affiliation: | (1) State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, 610059, China |
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Abstract: | As the Wenchuan Earthquake was of high magnitude and shallow seismic focus, it caused great damage and serious geohazards.
By the field investigation and the interpretation of remote-sensing information after the earthquake and by using means of
GIS technology, the distribution of geohazards triggered by the earthquake are analyzed and the conclusions are as follows:
(1) The earthquake geohazards showed the feature of zonal distribution along the earthquake fault zone and linear distribution
along the rivers; (2) the distribution of earthquake geohazards had a marked hanging wall effect, for the development density
of geohazards in the hanging wall of earthquake fault zone was obviously higher than that in the foot wall and the width of
strong development zone in the hanging wall was about 10 km; (3) the topographical slope was a main factor which controlled
the development of earthquake geohazards and a vast majority of hazards were distributed on the slopes of 20° to 50°; (4)
the earthquake geohazards had a corresponding relationship with the elevation and micro-landform, for most hazards happened
in the river valleys and canyon sections below the elevation of 1500 to 2000 m, particularly in the upper segment of canyon
sections (namely, the turning point from the dale to the canyon). Thin ridge, isolated or full-face space mountains were most
sensitive to the seismic wave, and had a striking amplifying effect. In these areas, collapses and landslides were most likely
to develop; (5) the study also showed that different lithologies determined the types of geohazards, and usually, landslides
occurred in soft rocks, while collapses occurred in hard rocks.
Supported by the Key Basic Research Program of the Ministry of Science and Technology of China (Grant No. 2008CB425800) |
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Keywords: | 5 12 Wenchuan Earthquake seismogenic geohazard distribution remote-sensing information hanging wall effect GIS analysis |
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