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

Abstract

This paper presents a new region-based preparatory factor, total flux (TF), for landslide susceptibility models (LSMs). TF takes into account the topography and hydrology conditions upstream of each gridded data cell and represents the total flux of water in the stream. The results show that TF is strongly associated with the occurrence of landslides and is a good preparatory factor for LSM. Using TF instead of a drainage distance factor in I-Lan region in Taiwan shows an improvement in the accuracy of the cumulative percentage of landslide occurrence of 44 and 14 % for the top 1 and 10 % susceptible areas, respectively. This significant improvement in accuracy in these high-risk areas is critical for preventing and mitigating the economic and human losses due to landslides.

Influences of the Shadow Inventory on a Landslide Susceptibility Model

“…A standard LSM based on the geometric mean of multivariables, including a newly introduced region-based preparatory TF factor, was developed to map the landslide susceptibility in I-Lan [25,26]. This LSM can be used to predict landslides by weighting various preparatory factors pf [27] according to their contributions, and to compute a landslide susceptibility index (LSI) using the geometric mean model [28,29].…”

“…After excluding the river channel and those regions outside the study area (annotated in blue), the area ratios of the landslide inventory and shadow inventory are 3.9% and 34.1%, respectively. The lithology map was provided by the Central Geological Survey (CGS) of Taiwan (1/50,000 scale), while the slope, aspect, and total flux (TF) were calculated from a 5-m resolution digital elevation model (DEM), which was produced and made available by the Ministry of Interior Affairs of Taiwan (see Figure 2 in [25]). Note that TF considers the topography and hydrology conditions upstream of each gridded data cell and represents the total flux of water in the stream, which is strongly associated with the occurrence of landslides and is a good preparatory factor for LSM [25].…”

“…The lithology map was provided by the Central Geological Survey (CGS) of Taiwan (1/50,000 scale), while the slope, aspect, and total flux (TF) were calculated from a 5-m resolution digital elevation model (DEM), which was produced and made available by the Ministry of Interior Affairs of Taiwan (see Figure 2 in [25]). Note that TF considers the topography and hydrology conditions upstream of each gridded data cell and represents the total flux of water in the stream, which is strongly associated with the occurrence of landslides and is a good preparatory factor for LSM [25]. Liu et al [25] demonstrated that drainage distance factor, defined as concentric multiringed buffer zones based on the distance of each cell from the main stream, may not be an accurate factor to represent the influence of neighboring cells.…”

“…Note that TF considers the topography and hydrology conditions upstream of each gridded data cell and represents the total flux of water in the stream, which is strongly associated with the occurrence of landslides and is a good preparatory factor for LSM [25]. Liu et al [25] demonstrated that drainage distance factor, defined as concentric multiringed buffer zones based on the distance of each cell from the main stream, may not be an accurate factor to represent the influence of neighboring cells. Because it may not properly represent the flux of water, likely responsible for the failure of slopes adjacent to streams.…”

“…Apart from three cell-based factors: slope, aspect, and lithology, Liu et al [25] demonstrated that the regional-based factor TF is strongly correlated with the occurrence of landslides. Therefore, TF can serve as a good pf too and Equation 1is refined as:…”