REAL-TIME MONITORING AND EARLY WARNING OF LANDSLIDES AT RELOCATED WUSHAN TOWN, THE THREE GORGE RESERVOIR, CHINA

A total of 4200 landslides have been identified in the Three Gorges Reservoir area. It is planned that a total of 3200 landslides (i.e., 75% of the total number of landslides) will be monitored. Since 2003, the authors have carried out a geo-hazard real-time monitoring and early warning project at relocated Wushan town (Wushan new town) in the Three Gorges Reservoir area. Its purpose is to establish monitoring and early warning demonstration station. The station has three main functions: (1) Internet-based, (2) Comprehensive monitoring, and (3) Early warning. Based on the landslide monitoring experience at the Three Gorges Reservoir area, the early warning critical value at Wushan new town is established and presented in this paper. The critical situation is divided into four levels: I level early warning (indicated as blue), II level early warning (indicated as yellow), III level early warning (indicated as orange), and IV level early warning (indicated as red). Judging from the Yuhuangge landslide monitoring data in this area since 2004, the Wushan new town is at the blue early warning level. However, monitoring data of displacement at deep borehole showed that the displacement increased 5 mm in five months with an average velocity 1.0 mm/month. The velocity is 10 times higher than that at the early deformation stage. For this reason, the early warning level is changed from blue to yellow, which means an accelerated deformation period and emphasizes the need for denser monitoring. Keywords: Landslide, Three Gorges Reservoir, real-time monitoring, early warning