Correction to: Evolution of hydro‑mechanical behaviours and its influence on slope stability for a post‑earthquake landslide: implications for prolonged landslide activity

Abstract. The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g., layering, preferential flow paths such as fissures) of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS) to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps).

Download Full-text

Three decades of landslide activity in western Nepal: new insights into trends and climate drivers

Landslides ◽

10.1007/s10346-021-01632-6 ◽

2021 ◽

Author(s):

A. Muñoz-Torrero Manchado ◽

S. Allen ◽

J. A. Ballesteros-Cánovas ◽

A. Dhakal ◽

M. R. Dhital ◽

...

Keyword(s):

Slope Stability ◽

Shallow Landslides ◽

Climate Change Signal ◽

Annual Number ◽

Demographic Development ◽

Landslide Activity ◽

Main Driver ◽

Long Term Trends ◽

Remote Sensing Techniques

AbstractIn recent decades, landslide disasters in the Himalayas, as in other mountain regions, are widely reported to have increased. While some studies have suggested a link to increasing heavy rainfall under a warmer climate, others pointed to anthropogenic influences on slope stability, and increasing exposure of people and assets located in harm’s way. A lack of sufficiently high-resolution regional landslide inventories, both spatially and temporally, has prevented any robust consensus so far. Focusing on Far-Western Nepal, we draw on remote sensing techniques to create a regional inventory of 26,350 single landslide events, of which 8778 date to the period 1992–2018. These events serve as a basis for the analyses of landslide frequency relationships and trends in relation to precipitation and temperature datasets. Results show a strong correlation between the annual number of shallow landslides and the accumulated monsoon precipitation (r = 0.74). Furthermore, warm and dry monsoons followed by especially rainy monsoons produce the highest incidence of shallow landslides (r = 0.77). However, we find strong spatial variability in the strength of these relationships, which is linked to recent demographic development in the region. This highlights the role of anthropogenic drivers, and in particular road cutting and land-use change, in amplifying the seasonal monsoon influence on slope stability. In parallel, the absence of any long-term trends in landslide activity, despite widely reported increase in landslide disasters, points strongly to increasing exposure of people and infrastructure as the main driver of landslide disasters in this region of Nepal. By contrast, no climate change signal is evident from the data.

Download Full-text

A conceptual model of the hydrological influence of fissures on landslide activity

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-8-11039-2011 ◽

2011 ◽

Vol 8 (6) ◽

pp. 11039-11073 ◽

Cited By ~ 2

Author(s):

D. M. Krzeminska ◽

T. A. Bogaard ◽

Th. W. J. van Asch ◽

L. P. H. van Beek

Keyword(s):

Slope Stability ◽

Preferential Flow ◽

Hydrological Regime ◽

Temporal Variations ◽

Hydrological Processes ◽

Flow Paths ◽

Meteorological Forcing ◽

Landslide Activity ◽

Preferential Flow Paths ◽

Slow Moving

Abstract. Hydrological processes control the behaviour of many unstable slopes and their importance for landslide activity is generally accepted. In slow-moving landslides differential displacement complicates the hydrological regime due to continuous opening and closing of the fissures and cracks, creating dynamic preferential flow path systems. The consequences of the appearance and destruction of these preferential flow paths is thus closely related to the formation of critical pore pressure and the resulting movement and persistence of fissure systems. This interaction may account for the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays. This research aims to investigate this interaction between slope stability and spatial and temporal variations in fissure patterns, which makes fissures act both as preferential flow paths for infiltration and as lateral groundwater drains. To this end, the hydrological processes that control exchange of water between the fissure network and the matrix has been included in a spatially distributed hydrological and slope stability model. The ensuing feedbacks in landslide activity were explored by running the model with the meteorological forcing of one year until a dynamic steady-state was achieved. The effect of fissure dynamics was evaluated by comparing simulations with static fissure patterns to those in which these patterns deform as function of the local stability.

Download Full-text

A model of hydrological and mechanical feedbacks of preferential fissure flow in a slow-moving landslide

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-11161-2012 ◽

2012 ◽

Vol 9 (10) ◽

pp. 11161-11197 ◽

Cited By ~ 1

Author(s):

D. M. Krzeminska ◽

T. A. Bogaard ◽

J.-P. Malet ◽

L. P. H van Beek

Keyword(s):

Slope Stability ◽

Preferential Flow ◽

Water Pressure ◽

Flow Paths ◽

Landslide Activity ◽

Hydrological Responses ◽

Preferential Flow Paths ◽

Slow Moving ◽

Groundwater Drainage ◽

Opening And Closing

Abstract. The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g. layering, preferential flow paths such as fissures) of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS) to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps).

Download Full-text

Three decades of landslide activity in western Nepal: New insights into trends and climate drivers

10.5194/egusphere-egu21-15848 ◽

2021 ◽

Author(s):

Alberto Muñoz-Torrero Manchado ◽

Simon Allen ◽

Juan Antonio Ballesteros-Canovas ◽

Amrit Dhakal ◽

Megh Raj Dhital ◽

...

Keyword(s):

Climate Change ◽

Slope Stability ◽

Google Earth ◽

Shallow Landslides ◽

Anthropogenic Factors ◽

Climate Change Signal ◽

Annual Number ◽

Landsat Images ◽

Intergovernmental Panel ◽

Landslide Activity

Landslide activity in the Himalaya region is hypothesized to have increased over the last decades, as suggested by exiting landslide databases and disaster inventories. This trend has been linked to an enhancement of heavy rainfall events under warming climate, but also to anthropogenic factors that influences the slope stability as well as to an increase of exposed of people and infrastructures in prone areas. Yet, as recognized by the Intergovernmental Panel on Climate Change (IPCC), such positive trends are still unclear, mostly due to the lack of baseline data with enough spatio-temporal resolution. Focusing on Far-Western Nepal, we draw on remote sensing techniques to create a multi-temporal regional landslide inventory for the period 1992-2018 over an area covering 6,460 km2. To this end, we systematically interpret geomorphologically high-resolution satellite imagery from Google Earth. Besides, we analyze multispectral differences from Landsat images to interannual date the initiation or reactivation of the interpreted landslides. This massive effort includes the digitalization of 26,350 landslide events, of which 8,778 were dated at an annual scale. These events serve as a basis for the analyses of landslide frequency relationships and trends in relation to annual precipitation and temperature datasets, derived from ERA-5 climate reanalysis. Our results show a strong correlation between the annual number of shallow landslides and the accumulated monsoon precipitation (r=0.74). Furthermore, warm and dry monsoons followed by especially rainy monsoons produce the highest incidence of shallow landslides (r=0.77). However, we find strong spatial variability in the strength of these relationships, which is linked to recent demographic development in the region. This highlights the role of anthropogenic drivers, and in particular, road cutting and land-use change, in amplifying the seasonal monsoon influence on slope stability. In parallel, the absence of any long-term trends in landslide activity, despite a widely reported increase in landslide disasters, points strongly to increasing exposure of people and infrastructure as the main driver of landslide disasters in this region of Nepal. Thus, our assessment could not determine evidence for any climate change signal related to landslide activity over this part of the Himalayas.

Download Full-text