A Demonstrative GPS-aided Automatic Landslide Monitoring System in Sichuan Province

In China, the geological disasters of landslide and mud-rock flows cause losses of over 1000 lives and total economic losses of over 10 billions of RMB each year. There have been about 90,000 identified landslide sites, mostly distributed in several southern and northwestern provinces of China. In the reservoir area of the Three-Gorge project only, over 1000 landslide sides have been identified. A joint research was launched involving authors from a number of scientific institutions to explore technologies and methodologies for landslide monitoring with focus on the characteristics of the geological disasters at the up and middle reaches of Yangtze River. This paper studies the combined technologies for landslides monitoring and presents a demonstrative automatic landslide monitoring system in a chosen ancient landslide site, where the creeping movement process continues since its latest large sliding on August 25, 1981. The landslide test-bed is 500 m long and 300 m wide located in the Ya’an-Xiakou area in Sichuan province. To study the mechanism of the sliding process, 15 permanent GPS monuments were built in the area for regular observations. Automatic ombrometers, digital thermometers, underground water-level-meter and ground fissure-displacement-meter were set-up as well. The data from these automatic sensors are collected and automatically sent to the data process centre in Beijing via the Beidou-1 communication satellite. The paper also compares the landslide results from three GPS observing campaigns, demonstrates the feasibility to identify the displacements at the accuracy level of 2 mm using the dual-frequency GPS receivers. The results are encouraging and further analyses will be conducted, considering influences of non-GPS measurements.