Evaluation of landslide hazards at Herth, Chitral, Pakistan

摘要

The main purpose of this paper was to evaluate landslide hazards at Herth, Chitral, Pakistan. Based on a comprehensivecross-disciplinary research methodology, it was found that the geology of the area is complex with deformations in variousdirections. In a semiarid climate (BSk), large variations in rainfall (80 mm in spring and 8 mm in summer) and temperature(− 1 ℃ in January and 35 ℃ in July) affect the temporal distribution of landslides in the area. Overlaying weak weatheredrocks, the 6–12 m thick soft soils exhibit up to 8-m-deep tension cracks and several shallow slope failures. Likewise, thehigh-relief mountains (2235–3155 m) mainly face southwards (40%) and northwards (35%) with 58% areas at inclinationsof 15°–45° and 39% area with up to 15° slopes. The surface soils are mainly clayey sands with occasional silts and remainunsaturated due to high drainage in the field. The stress–strain behavior is identical to loose sands with the residual frictionangle close to the peak value (32°–34°) indicating the lowest possible shear strength. Finally, the landslide areas have generallyincreased from 1985 through 2014 for Karimabad (0.32–0.84 km~2), Ajrandeh (0.3–0.74 km~2) and Shah (0.13–0.42 km~2).