Landslide susceptibility mapping by using a geographic information system (GIS) along the China–Pakistan Economic Corridor (Karakoram Highway), Pakistan

Sajid Ali,Klaus Reicherter,Peter Biermanns,Rashid Haider

doi:10.5194/nhess-19-999-2019

Abstract

Abstract. The Karakoram Highway (KKH) is an important route, which connects northern Pakistan with Western China. Presence of steep slopes, active faults and seismic zones, sheared rock mass, and torrential rainfall make the study area a unique geohazards laboratory. Since its construction, landslides constitute an appreciable threat, having blocked the KKH several times. Therefore, landslide susceptibility mapping was carried out in this study to support highway authorities in maintaining smooth and hazard-free travelling. Geological and geomorphological data were collected and processed using a geographic information system (GIS) environment. Different conditioning and triggering factors for landslide occurrences were considered for preparation of the susceptibility map. These factors include lithology, seismicity, rainfall intensity, faults, elevation, slope angle, aspect, curvature, land cover and hydrology. According to spatial and statistical analyses, active faults, seismicity and slope angle mainly control the spatial distribution of landslides. Each controlling parameter was assigned a numerical weight by utilizing the analytic hierarchy process (AHP) method. Additionally, the weighted overlay method (WOL) was employed to determine landslide susceptibility indices. As a result, the landslide susceptibility map was produced. In the map, the KKH was subdivided into four different susceptibility zones. Some sections of the highway fall into high to very high susceptibility zones. According to results, active faults, slope gradient, seismicity and lithology have a strong influence on landslide events. Credibility of the map was validated by landslide density analysis (LDA) and receiver operator characteristics (ROC), yielding a predictive accuracy of 72 %, which is rated as satisfactory by previous researchers.

Highlights

Landslides are a result of different geodynamic processes and represent a momentous type of geohazard, causing economic and social loss by damaging infrastructure and buildings (Vallejo and Ferrer, 2011)
Active faults, slope gradient, seismicity and lithology have a strong influence on landslide events
Presence of a large number of rock/debris falls (37) in Jijal–Dassu section is due to steep topography formed by deep river incision in ultramfics (Jijal Complex), amphibolites (Kamila amphibolites) and gabbronorites (Chilas Complex) of Kohistan Island Arc, whereas stress release joints with short persistence in Sazin–Chilas section are responsible for huge boulder falls (> 6 m3)

Summary

Introduction

Landslides are a result of different geodynamic processes and represent a momentous type of geohazard, causing economic and social loss by damaging infrastructure and buildings (Vallejo and Ferrer, 2011). Conditioning factors include relief, lithology, geological structure, geomechanical properties and weathering, whereas precipitation, seismicity, change in temperature, and static or dynamic loads are triggering factors. Variations in these factors affect the occurrence of landslides. Some lithologies are more permeable and allow water to infiltrate and to increase the pore water pressure This increase in pore water pressure during rainfall events affects shear strength of the rock mass and slope stability (Barchi et al, 1993; Cardinali et al, 1994), whereas the less pervious rock masses have low infiltration and high runoff leading to debris and mud flows (Dramis et al, 1988; Ellen et al, 1993; Canuti et al, 1993). Sheared and highly jointed rock masses contain shallow slope failures, whereas rockfalls are concen-

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Discussion

Conclusion