Applicability of Geomorphic Index for the Potential Slope Instability in the Three River Region, Eastern Tibetan Plateau

Abstract

Geomorphic indices (e.g., the normalized channel steepness index (Ksn) and the stream length-gradient index (SL)) highlight changes in fluvial shapes and gradients. However, the application of these indices was seldom used to identify potential landslide zones. In this study, we used the Ksn and SL indices to detect the significant variations in the stream power along river reaches, which are anomalies associated with landslides, in the Zengqu River watershed, the upper reaches of the Jinsha River. Most of the landslide anomalies originate along the trunk and surrounding tributaries below the knickpoint of the mainstream. This suggests an erosional wave is migrating upstream throughout the drainage area. The fluvial incision may generate over-steepened hillslopes, which could fail in the future. In addition, the divide asymmetry index (DAI) predicts the direction of the divide as the headwaters migrate toward lower relief, higher elevation surfaces. Landslides are expected to occur as the unstable divide migrates. The proposed methodology can benefit the detection and characterization of potential landslide zones. It should improve hazard and risk analysis and the identification of drainage network areas associated with landslides.

Improving landslide inventories by combining satellite interferometry and landscape analysis: the case of Sierra Nevada (Southern Spain)

“…Despite their limitations, we conclude that both DInSAR techniques (e.g. Notti et al 2010;Bianchini et al 2013;Bekaert et al Troiani et al 2017;Liu et al 2021) can optimise the landslide detection in mountainous areas. Our results demonstrate that both methods not only can be well complemented, but also limitations of each one can be compensated.…”

“…Knickzones are reflected as clearly higher values than the rest of values along the river profile, which are considered as anomalous values. The successful application of gradient-related indexes to detect landslides has already been proven in several studies (Pánek et al 2007;El Hamdouni et al 2010;Walsh et al 2012;Troiani et al 2014Troiani et al , 2017Penna et al 2015;De Palézieux et al 2018;Ahmed et al 2019;Subiela et al 2019;Piacentini et al 2020;Gu et al 2021;Liu et al 2021). In recent years, GIS platforms and high-resolution DEMs have facilitated the application of geomorphometric techniques in terms of time-consumption and cost-effectiveness (Troiani et al 2014(Troiani et al , 2017.…”

Structural control on drainage pattern development of the western Taiwan orogenic wedge

“…Based on the spatial resolutions of the images used, the smallest landslide identified in this study has a diameter of about 10 m. Since landslides that breach the drainage divide would cause the divide to move (e.g., Dahlquist et al, 2018), we only focused on landslides that sourced at the divide crest. A persistently higher landslide frequency on one side of the divide would tend to move the divide in the opposite direction (e.g., Hovius et al, 1998; Liu et al, 2021; Willett et al, 2014; Figure 3). Satellite images from multiple years provide us the information about whether the landslides are short‐lived or persistent, as well as if they indeed affect the crest of the divides.…”