Modelling landslide hazards under global changes: the case of a Pyrenean valley

Abstract

Abstract. Several studies have shown that global changes have important impacts in mountainous areas, since they affect natural hazards induced by hydrometeorological events such as landslides. The present study evaluates, through an innovative method, the influence of both vegetation cover and climate change on landslide hazards in a Pyrenean valley from the present to 2100. We first focused on assessing future land use and land cover changes through the construction of four prospective socioeconomic scenarios and their projection to 2040 and 2100. Secondly, climate change parameters were used to extract the water saturation of the uppermost layers, according to two greenhouse gas emission scenarios. The impacts of land cover and climate change based on these scenarios were then used to modulate the hydromechanical model to compute the factor of safety (FoS) and the hazard levels over the considered area. The results demonstrate the influence of land cover on slope stability through the presence and type of forest. The resulting changes are statistically significant but small and dependent on future land cover linked to the socioeconomic scenarios. In particular, a reduction in human activity results in an increase in slope stability; in contrast, an increase in anthropic activity leads to an opposite evolution in the region, with some reduction in slope stability. Climate change may also have a significant impact in some areas because of the increase in the soil water content; the results indicate a reduction in the FoS in a large part of the study area, depending on the landslide type considered. Therefore, even if future forest growth leads to slope stabilization, the evolution of the groundwater conditions will lead to destabilization. The increasing rate of areas prone to landslides is higher for the shallow landslide type than for the deep landslide type. Interestingly, the evolution of extreme events is related to the frequency of the highest water filling ratio. The results indicate that the occurrences of landslide hazards in the near future (2021–2050 period, scenario RCP8.5) and far future (2071–2100 period, scenario RCP8.5) are expected to increase by factors of 1.5 and 4, respectively.

Impacts of future climate and land cover changes on landslide susceptibility: regional scale modelling in the Val d’Aran region (Pyrenees, Spain)

“…Rainfall-triggered landslides are an important hazard in mountainous regions. Recent studies concluded that land use and land cover (LULC) and climate changes will have an important effect on the frequency and magnitude of rainfall-induced landslides (Gariano and Guzzetti 2016;Persichillo et al 2017;Bernardie et al 2021). However, the assessment of the effects of LULC and climate changes on shallow slides is complex and uncertainties are still very large.…”

Measurement and inversion strategies for 3‐D resistivity surveys with vector arrays

“…General information on landslides in the Pyrénées region and geology of the area can be found in Bernardie et al . (2021) and Batailles & Lespine (2019). The Viella slope is composed of a complex mixture of sedimentary material associating torrential deposits, moraine deposits (from the Bastan ice glacier), colluvium, screes and weathered blocks of shales from previous historical rockfalls triggered from the overhanging cliff.…”

The Role of Citrus Groves in Rainfall-Triggered Landslide Hazards in Uwajima, Japan

“…First, this study only included one rainfall event, several events would have been desirable for generalization. Second, historical land use changes and landslides were not considered, which may affect the current landslide hazard [59,60]. Third, the mechanism that leads to higher landslide initiation in fruit groves compared with forests could not be clarified.…”