Seismic Landslides and the Environmental Impact in the Middle Reach of Daduhe River
There are 15 large-scaled rock landslides in the middle reach of Daduhe River in the western Sichuan. As they even dammed the Daduhe River for a long time, the dammed accumulation are well widely developed, relatively wide bottom valley have been formed in the reach. Now, there are about 80000 people lived in the valley of the reach, as the region is in high intensity (VIII-IX), the latest large earthquake (magnitude is 7.7)happened in 1876 and dammed the River, causing over ten thousand people die in the huge flood after the dam broke. As the construction velocity is faster than before, the hydropower station, highway, new village construction are put on the schedule, but people seem forgetting the historical earthquakes and seismic landside’s impact, hidden dangers may come at any time. The present paper tries to introduce the characteristics of the landslides and its environment impacts such as deep overburden, soft soil, sand liquefaction and landslide reactive. So as to call peoples’ attention for the environment during they are engaged in the large scale construction. Based on the RS interpretation and field comprehensive investigations, 15 large scaled rock landslides have been found in the reach, the volume of each is over 1000,000m3, although the remains are stable on the whole, the front part is potential unstable, if they are active triggered by the future earthquake or storm, they can dam the Daduhe River again and cause huge geo-hazards. Several ideas can be concluded as follows：(1)The reach is composed of Proterozoic acid intrusive rock and underwent several large tectonic movements, the rock mass is cut by structural planes formed in the different tectonic epoch; (2) The middle reach of Daduhe River is one part of SN strike tectonic belt in China, the main advantageous structural planes is SN strike, which is parallel to the flow direction of Daduhe River; (3) The reach is within a high intensity region with over VIII degrees, seismic landslides are well developed and they are easily reactive in the future, people confront with the deep overburden, soft soil, sand liquefaction; (4) the villages and town is generally located on the second Terrace and easily influenced by the seismic large slides, their vulnerability is high; (5) engineering measurements are necessary to protect the town villages and it is urgent to built disaster warning system.
Qing Yang, Li Hua Zhu, Jing Jing He, Zeng Feng Yan and Rui Ren
Y. S. Wang et al., "Seismic Landslides and the Environmental Impact in the Middle Reach of Daduhe River", Advanced Materials Research, Vols. 368-373, pp. 1965-1970, 2012