Effects of rainfall spatial variability and intermittency on shallow landslide triggering patterns at a catchment scale

The occurrence of shallow landslides is often associated with intense and prolonged rainfall events, where infiltrating water reduces soil strength and may lead to abrupt mass release. Despite general understanding of the role of rainfall water in slope stability, the prediction of rainfall-induced landslides remains a challenge due to natural heterogeneity that affect hydrologic loading patterns and the largely unobservable internal progressive failures. An often overlooked and potentially important factor is the role of rainfall variability in space and time on landslide triggering that is often obscured by coarse information (e.g., hourly radar data at spatial resolution of a few kilometers). To quantify potential effects of rainfall variability on failure dynamics, spatial patterns, landslide numbers and volumes, we employed a physically based “Catchment-scale Hydromechanical Landslide Triggering” (CHLT) model for a study area where a summer storm in 2002 triggered 51 shallow landslides. In numerical experiments based on the CHLT model, we applied the measured rainfall amount of 53 mm in different artificial spatiotemporal rainfall patterns, resulting in between 30 and 100 landslides and total released soil volumes between 3000 and 60,000 m3 for the various scenarios. Results indicate that low intensity rainfall below soil's infiltration capacity resulted in the largest mechanical perturbation. This study illustrates how small-scale rainfall variability that is often overlooked by present operational rainfall data may play a key role in shaping landslide patterns.

[1]  Kang-Tsung Chang,et al.  Analysing the Relationship Between Typhoon‐Triggered Landslides and Critical Rainfall Conditions , 2008 .

[2]  Bodo Ahrens,et al.  Rainfall downscaling in an alpine watershed applying a multiresolution approach , 2003 .

[3]  Martyn P. Clark,et al.  Probabilistic forecasting of shallow, rainfall-triggered landslides using real-time numerical weather predictions , 2008 .

[4]  Patrick Arnaud,et al.  Influence of rainfall spatial variability on flood prediction , 2002 .

[5]  R. Rigon,et al.  Potential for landsliding: Dependence on hyetograph characteristics , 2005 .

[6]  Giacomo Bertoldi,et al.  Modelling the probability of occurrence of shallow landslides and channelized debris flows using GEOtop‐FS , 2008 .

[7]  D. Montgomery,et al.  A physically based model for the topographic control on shallow landsliding , 1994 .

[8]  Alexis Berne,et al.  A network of disdrometers to quantify the small‐scale variability of the raindrop size distribution , 2011 .

[9]  K. Beven,et al.  ASSESSING THE EFFECT OF SPATIAL PATTERN OF PRECIPITATION IN MODELING STREAM FLOW HYDROGRAPHS , 1982 .

[10]  D. Bae,et al.  Quantitative Comparison of the Spatial Distribution of Radar and Gauge Rainfall Data , 2012 .

[11]  C. Mullins,et al.  The strength of unsaturated mixtures of sand and kaolin and the concept of effective stress , 1984 .

[12]  Kaoru Takara,et al.  A distributed hydrological–geotechnical model using satellite-derived rainfall estimates for shallow landslide prediction system at a catchment scale , 2010 .

[13]  Rex L. Baum,et al.  Rainfall characteristics for shallow landsliding in Seattle, Washington, USA , 2006 .

[14]  D. Or,et al.  An analytical fiber bundle model for pullout mechanics of root bundles , 2011 .

[15]  Richard M. Iverson,et al.  Landslide triggering by rain infiltration , 2000 .

[16]  W. Krajewski,et al.  Scale Dependence of Radar Rainfall Uncertainty: Initial Evaluation of NEXRAD’s New Super-Resolution Data for Hydrologic Applications , 2010 .

[17]  J. Parlange,et al.  PONDING TIME FOR VARIABLE RAINFALL RATES , 1976 .

[18]  D. Or,et al.  Hydromechanical triggering of landslides: From progressive local failures to mass release , 2012 .

[19]  D. Montgomery,et al.  Spatial patterns of rainfall and shallow landslide susceptibility , 2009 .

[20]  L. Ayalew,et al.  The application of GIS-based logistic regression for landslide susceptibility mapping in the Kakuda-Yahiko Mountains, Central Japan , 2005 .

[21]  M. Schaap,et al.  ROSETTA: a computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions , 2001 .

[22]  Christoph Hinz,et al.  Sensitivity of point scale surface runoff predictions to rainfall resolution , 2007 .

[23]  David R. Montgomery,et al.  Topographic controls of landslides in Rio de Janeiro: field evidence and modeling , 2004 .

[24]  Kang-Tsung Chang,et al.  Application of radar data to modeling rainfall-induced landslides , 2009 .

[25]  J. Godt,et al.  A closed‐form equation for effective stress in unsaturated soil , 2010 .

[26]  D. A. Woolhiser,et al.  Impact of small-scale spatial rainfall variability on runoff modeling , 1995 .

[27]  M. Rossi,et al.  Rainfall thresholds for the initiation of landslides in central and southern Europe , 2007 .

[28]  A. Brenning.  Spatial prediction models for landslide hazards: review, comparison and evaluation , 2005 .

[29]  J. Parlange,et al.  A simple accurate method to predict time of ponding under variable intensity rainfall , 2007 .

[30]  M. Dacey.  A NOTE ON THE DERIVATION OF NEAREST NEIGHBOR DISTANCES. , 1960 .

[31]  Witold F. Krajewski,et al.  An analysis of small-scale rainfall variability in different climatic regimes , 2003 .

[32]  D. R. Dawdy,et al.  Effect of rainfall variability on streamflow simulation , 1969 .

[33]  S. Sorooshian,et al.  Measurement and analysis of small-scale convective storm rainfall variability , 1995 .

[34]  David A. Woolhiser,et al.  EFFECT OF STORM RAINFALL INTENSITY PATTERNS ON SURFACE RUNOFF , 1988 .

[35]  George H. Taylor,et al.  High-quality spatial climate data sets for the United States and beyond , 2000 .

[36]  Peter Lehmann,et al.  Rainfall‐triggered shallow landslides at catchment scale: Threshold mechanics‐based modeling for abruptness and localization , 2013 .

[37]  Giovanni B. Crosta,et al.  Distributed modelling of shallow landslides triggered by intense rainfall , 2003 .

[38]  Toru Higuchi,et al.  Development of progressive landslide failure in cohesive materials , 2005 .

[39]  D. Or,et al.  Pullout tests of root analogs and natural root bundles in soil: Experiments and modeling , 2011 .

[40]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[41]  C. Frei,et al.  The climate of daily precipitation in the Alps: development and analysis of a high‐resolution grid dataset from pan‐Alpine rain‐gauge data , 2014 .

[42]  M. Chigira,et al.  Weathering profile of non-welded ignimbrite and the water infiltration behavior within it in relation to the generation of shallow landslides , 2005 .

[43]  Indrajeet Chaubey,et al.  Uncertainty in the model parameters due to spatial variability of rainfall , 1999 .

[44]  Jeffrey J. McDonnell,et al.  On the interrelations between topography, soil depth, soil moisture, transpiration rates and species distribution at the hillslope scale , 2006 .

[45]  J. Philip.  THE THEORY OF INFILTRATION: 1. THE INFILTRATION EQUATION AND ITS SOLUTION , 1957 .

[46]  D. Brien,et al.  Acute sensitivity of landslide rates to initial soil porosity. , 2000, Science.

[47]  P. J. Clark,et al.  Distance to Nearest Neighbor as a Measure of Spatial Relationships in Populations , 1954 .

[48]  W. Dietrich,et al.  Testing a model for predicting the timing and location of shallow landslide initiation in soil‐mantled landscapes , 2003 .

[49]  Marco Borga,et al.  Regional frequency analysis of extreme precipitation in the eastern Italian Alps and the August 29, 2003 flash flood , 2007 .

[50]  M. Rossi,et al.  The rainfall intensity–duration control of shallow landslides and debris flows: an update , 2008 .

[51]  Jacques Lavabre,et al.  Impact of imperfect rainfall knowledge on the efficiency and the parameters of watershed models , 2001 .

[52]  David R. Montgomery,et al.  A process-based model for colluvial soil depth and shallow landsliding using digital elevation data , 1995 .

[53]  F. Graf,et al.  Effects of forests on shallow landslides - case studies in Switzerland , 2009 .

[54]  V. Doyuran,et al.  Data driven bivariate landslide susceptibility assessment using geographical information systems: a method and application to Asarsuyu catchment, Turkey , 2004 .

[55]  Peter Lehmann,et al.  Spatial statistical modeling of shallow landslides—Validating predictions for different landslide inventories and rainfall events , 2011 .

[56]  Fausto Guzzetti,et al.  Landslides triggered by the 23 November 2000 rainfall event in the Imperia Province, Western Liguria, Italy , 2004 .

[57]  Witold F. Krajewski,et al.  Radar for hydrology: unfulfilled promise or unrecognized potential? , 2013 .

[58]  Adrian M. Altenhoff,et al.  A gridded hourly precipitation dataset for Switzerland using rain‐gauge analysis and radar‐based disaggregation , 2010 .

[59]  N. Caine,et al.  The Rainfall Intensity - Duration Control of Shallow Landslides and Debris Flows , 1980 .

[60]  Rex L. Baum,et al.  Transient deterministic shallow landslide modeling: Requirements for susceptibility and hazard assessments in a GIS framework , 2008 .

[61]  Alexis Berne,et al.  Quantification of the Small-Scale Spatial Structure of the Raindrop Size Distribution from a Network of Disdrometers , 2012 .

[62]  C. Daly,et al.  Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States , 2008 .

[63]  Torsten Schaub,et al.  The variability of root cohesion as an influence on shallow landslide susceptibility in the Oregon Coast Range , 2001 .