Rainfall Intensity Temporal Patterns Affect Shallow Landslide Triggering and Hazard Evolution

Fan, Linfeng; Lehmann, Peter; Chen, Kewei; Or, Dani

doi:10.1029/2019gl085994

Cited by 31 publications

(19 citation statements)

References 56 publications

(66 reference statements)

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“…Hoober et al (2017) pointed to the role of intensity profile in gully erosion processes, while Ni and Song (2020) drew attention to its importance in debris flow initiation. Further relevance to mass movement has been documented in the case of shallow landslide occurrence (Fan et al, 2020). In relation to stream sediment transport, intensity profile has been under-explored, though Yuan et al (2019) established this in relation to flash flood occurrence in small watersheds.…”

Section: The Path Forward In the Study Of Rainfall Intensity And Geomorphologymentioning

confidence: 99%

Rainfall intensity in geomorphology: Challenges and opportunities

Dunkerley

2020

Progress in Physical Geography: Earth and Environment

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Rainfall arrival at the land surface drives or influences many geomorphic processes. These range from the mechanisms through which vegetation transforms rain into erosive gravity drops or stemflow, infiltration and water partitioning at the soil surface, the drop-impact sealing of soil surfaces, splash, sheet, and gully erosion, and triggering of the various forms of mass movement including landslides and debris flows. Rainfall intensity is a key influence on many of these mechanisms but is not a straightforward parameter to quantify, partly owing to the customary aggregation of rainfall data to hourly or other clock-time totals. This aggregation conceals intensity fluctuations including erosive ‘intensity bursts’ as well as the intermittency of rainfall. Nevertheless, much research shows that rainfall intensity over short time periods – 10–30 minutes – has great explanatory power. Much of our understanding of the influence of rainfall intensity is based on rainfall simulation experiments, but the value of the findings is limited because simulation is normally carried out using a high and constant rainfall intensity, quite unlike natural rainfall. This has limited our ability to build an understanding of the other important aspects of rainfall intensity, including, critically, its time variation and changed character among different environments – arid, temperate, or tropical. Thus, significant challenges and opportunities remain in the exploration of rainfall intensity in relation to geomorphology and geomorphic processes.

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Section: The Path Forward In the Study Of Rainfall Intensity And Geomorphologymentioning

confidence: 99%

Rainfall intensity in geomorphology: Challenges and opportunities

Dunkerley

2020

Progress in Physical Geography: Earth and Environment

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“…For example, despite similar total rainfall amounts (61.6 and 61.0 mm, respectively), the long‐lasting rainfall of D = 16 hr and P = 5 years (rainfall intensity 3.85 mm hr −1 ) resulted in far larger landslide volumes than the short rainfall of D = 2 hr and P = 50 years (rainfall intensity 30.5 mm hr −1 ). The contrasting different landslide activities induced by these two rainfall scenarios highlight the impacts of rainfall intensity temporal patterns on landslide triggering due to limiting infiltration capacity and loading in case of high rainfall intensities (Fan et al., 2020).…”

Section: Resultsmentioning

confidence: 99%

“…We approximate legacy landslide regions by the areas where landslide hazard exceeds a certain level. Here, we specifically account for the impacts of rainfall I‐D‐Fs on landslide hazard evolution (Fan et al., 2020). We apply rainfall scenarios with varying rainfall intensities and durations to simulate landslide triggering and runout passage in the pristine catchments (with steady state soil depths) and then deduce landslide hazard.…”

Section: Resultsmentioning

confidence: 99%

The Lasting Signatures of Past Landslides on Soil Stripping From Landscapes

Fan

Lehmann

Chen

et al. 2021

Water Resources Research

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Rainfall-induced shallow landslides represent a ubiquitous natural hazard in mountainous regions (Sidle & Ochiai, 2006) and exert critical control on sediment transfer, channel morphology, and landscape evolution (Hovius et al., 2000;Korup et al., 2007;Larsen et al., 2010). Evidence suggests that landslides are more likely to occur in historical landslide areas with favorable local climate and topography where soil depth is modified by landslide stripping and subsequently restored by soil regeneration (Mirus et al., 2017;Samia et al., 2017). Rainfall-induced shallow landslides typically strip the soil mantle and expose the underlying bedrock. The reduced soil depths in the stripped region may recover with soil regeneration rates that are primarily determined by soil development (through pedogenesis and bedrock weathering, often termed "soil production") and soil transport which are affected by local climate and biological perturbation (e.g., Dietrich et al., 1995;Heimsath et al., 1997). The transport of debris from the surrounding hillslopes to bedrock hollows and to channels is caused by different mechanisms such as soil creep, animal burrowing, and tree throw. Even though soils do not physically diffuse due to molecular interactions such as with heat or solutes, the slow local spreading of soil material resembles diffusion in landscape scale transport models expressed as soil diffusivity (Reneau & Dietrich, 1991), hence soil diffusivity is not a soil physical property, but a spreading parameter (e.g., Heimsath et al., 1997) reflecting soil properties such as grain size distribution and local factors such as bioturbation, climate and vegetation. The soil production by bedrock weathering is an outcome of complex interplay of physical, chemical, and biogenic process (Birkeland, 1999). The imprint of historical landslide stripping and subsequent soil regeneration on local topography and soil depth, in turn, influences the characteristics (e.g., timing, location, volume) of future landslide triggering and sediment production and delivery to fluvial systems (Crozier & Preston, 1999;Parker et al., 2016). In this paper, we term effects of past landslide stripping and subsequent soil regeneration on future landslide characteristics and related geophysical processes (e.g., fluvial sediment dynamics) as "landslide legacy effects" with cumulative historical landslides termed "legacy landslides." This resembles the notion of "path-dependent landsliding" proposed by Temme et al. (2020) for causal relations between consecutive landslides. However, "landslide legacy" combines imprints of past landslide events with subsequent soil regeneration over soil generation and depth evolution time scales. Hence, regions affected by "legacy landslides" are areas that experienced repeated mass wasting and subsequent soil regeneration in the past and are not limited to the neighborhoods of individual landslides triggered

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“…The average annual rainfall ranges from 1300 to 2500 mm. The landslide and debris ow caused by rain are the most common types of geological hazard in this area, and show the characteristics of the small scale of individual hazard point, a large number of groups, and wide distribution range (Chen et al 2006;Fan et al 2020;. The results show that rainfall is the direct triggering factor of this kind of landslide and debris ow.…”

Section: Introductionmentioning

confidence: 86%

Group-occurring landslides and debris flows caused by the continuous heavy rainfall in June 2019 in Mibei Village, Longchuan County, Guangdong Province, China

Bai

Feng

et al. 2021

Nat Hazards

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From June 10th to 13th, 2019, a continuous heavy rainfall occurred in Longchuan County, Guangdong Province, causing many landslide hazards. Among Longchuan County districts, Mibei village is one of the hardest-hit areas and suffered severe losses. In this paper, eld investigation, remote sensing image interpretation , and UAV aerial photography were used to investigate and analyze hazard characteristics.Combined with rainfall monitoring data, laboratory and eld tests data, and existing research results, the characteristics and failure mechanism of group-occurring landslides in Mibei village were studied.Because of the continuous heavy rainfall, 327 landslides occurred in the study area, mainly distributed in the north of the Mibei river and along the X158 road. The terrain slope of landslide hazards ranged from 35° to 45°, and the slope structure can be divided into two types. Granite residual soil was the main part of landslide mass, and sliding surface developed along with the interface between bedrock and covering layer. The continuous heavy rainfall from June 10th to 13th was the main triggering factor of the disaster.The total precipitation was 281.3 mm, and the rainfall on June 10th was 153.5 mm. The rain led to the continuous increase of volume water content in granite residual soil and completely weathered granite.The shear strength and parameters of the two materials changed differently, and slope stability continued to decrease, and then landslides occurred under terrain conditions and engineering excavation space. Untimely support and unreasonable support measures for the excavation slope exacerbated the disaster.The development degree of debris ows in the study area was very low, and debris ows were shown as the secondary disaster of landslides. The branch gully terrain is the key to transforming the landslide into the debris ow, and a large amount of loose deposits in the main gully will become the potential source of debris ow in the future.

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Rainfall Intensity Temporal Patterns Affect Shallow Landslide Triggering and Hazard Evolution

Cited by 31 publications

References 56 publications

Rainfall intensity in geomorphology: Challenges and opportunities

Rainfall intensity in geomorphology: Challenges and opportunities

The Lasting Signatures of Past Landslides on Soil Stripping From Landscapes

Group-occurring landslides and debris flows caused by the continuous heavy rainfall in June 2019 in Mibei Village, Longchuan County, Guangdong Province, China

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