Regional assessment of landslide impact in the Three Gorges area, China, using ASTER data: Wushan-Zigui

Abstract

This paper is focussed on the hazard impact of landslides in the Three Gorges, and represents the progression of our ongoing study on regional land instability assessment in the Three Gorges area using imagery data from the Advanced Spaceborne Thermal Emission Radiometer (ASTER). The key development here is the establishment of a model that integrates land instability with several factors that can relate hazard to human life, such as slope failures occurring in proximity to built-up areas and roads, and areas of high landslide risk along the bank of Yangtze and its major tributaries. The method correctly identifies some of the known destructive landslides in the region, like Qianjiangping and Huangtupo, as belonging to areas of potentially high landslide impact. Our results suggest that several population centres, including the towns of Wushan and Badong, are rated at high landslide hazard levels. This study highlights the importance of differentiating between landslide types within susceptibility assessment, and identifies those locations in the Three Gorges where the probability of landslide occurrence with negative impact to life and property is greatest.

Three Gorges Dam stability monitoring with time-series InSAR image analysis

“…Figure 9(a) relates to a target on top of the dam and (b) to a target on the tail water platform. Figure 9(c) and (d) show the upriver-downriver water level difference and upriver water level respectively for the duration of data acquisition 2) , from which, similar trends can be observed. The three red dashed lines in Figure 9 indicate the 2) The hydrologic data were acquired from the website of the Three Gorges Project Corporation (http://www.ctgpc.com.cn).…”

“…Owing to the high pressure of the reservoir on the riverbed and water infiltration, there is potential crust instability along the river. The crustal structure and dynamic variations in the gravity field in this area have been studied after the river was dammed [1][2][3]. Besides the rising water, the weight of the dam itself has applied substantial pressure on the riverbed crust and caused deformation.…”

A new region-based preparatory factor for landslide susceptibility models: the total flux

“…For example, the proximity to a drainage pattern has been considered as a contributing factor to landslide occurrence, as streams can adversely affect the stability of the adjacent slope by eroding the toe and/or saturating the slope (Gökceoglu and Aksoy 1996). The drainage distance factor, DD, expressed as concentric multi-ringed buffer zones based on the distance of each cell from the main stream, has thus been utilized to capture this effect in LSM (Fourniadis et al 2007;van Westen et al 2003). However, using DD buffers implies that all cells within the same buffer zone have the same landslide susceptibility.…”

Observing Dam’s Movements with Spaceborne SAR Interferometry

“…Such subset may lead to lower accuracy of estimation of deformation rates; (3) considering distributed (non-dominant) targets, a spatial filtering is applied to enhance the signal to noise ratio of the interferometric phase. Dam (02-08/2011) Since 1994, the mass of water in the 660 km long reservoir behind Three Gorges Dam (TGD) causes instability of mountain slopes, increasing occurrence of block slides, rockfalls and shallow debris-slides in the upriver areas of the dam (Fourniadis et al 2007), cumulating into huge landslides in 2003,2007,2009. Deformations were identified using QPSI in the area of Badong, in the height about 400 m above the Yangtze River (Perissin et al 2007b).…”