Debris-flow hazards in the Blue Ridge of central Virginia

Wieczorek, Gerald F.; Morgan, Benjamin A.; Campbell, Russell H.

doi:10.2113/gseegeosci.6.1.3

Cited by 132 publications

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“…Points are average of the 10 highest rainfall values around SLL. SC: Santa Catalina Mountains, Arizona (Webb et al, 2008); PR: Puerto Rico (Larsen and Simon, 1993); BR: Blue Ridge, Virginia (Wieczorek et al, 2000); CO: southern Rocky Mountains, Colorado (Coe et al, 2008). …”

Section: Threshold Of Slope Failurementioning

confidence: 99%

Occurrence of landslides during the approach of tropical cyclone Juliette (2001) to Baja California Sur, Mexico

Antinao¹,

Farfán²

2013

Atmósfera

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El acercamiento del ciclón tropical Juliette en 2001 a la península de Baja California provocó por lo menos 419 deslizamientos. Éstos corresponden en su mayoría a derrumbes someros de extensión reducida que fueron convertidos rápidamente en flujos de detritos para ser exportados de las áreas montañosas hacia áreas bajas. Los factores principales que afectan la ocurrencia de deslizamientos en esta zona son la precipitación total y su intensidad, así como la orientación, la geología y la vegetación. Se pueden distinguir dos procesos como iniciadores de los derrumbes. El primero de ellos es la acumulación de escorrentía por precipitación intensa sobre rocas expuestas, lo cual genera exceso de escurrimiento superficial que acarrea regolito. Éste es el proceso principal en topografía cóncava. La combinación de viento y de exceso de escurrimiento en las pendientes altas convexas o planas constituye un proceso secundario relacionado con la heterogeneidad de las asociaciones de vegetación en el límite entre los bosques tropical seco y de roble. Los árboles arrancados desprendieron bloques completos de regolito y roca, lo cual preparó las laderas para la concentración adicional de escurrimiento superficial. Se ha estimado una curva para el umbral de deslizamientos en esta región. Asimismo, con base en el análisis de la información histórica, se ha determinado que tormentas como Juliette se acercan al sur de la península en promedio una vez cada 100 años. Las estimaciones de la denudación provocada directamente por deslizamientos se ubican en la parte más alta del espectro para un margen tectónico pasivo. Estas estimaciones deben considerarse en la toma de decisiones vinculadas con el manejo de los recursos hídricos en esta región. Los resultados acentúan la necesidad de contar con una representación más detallada de la distribución espacial de la precipitación y vientos para esta región montañosa afectada por ciclones tropicales. ABSTRACTThe approach of tropical cyclone (TC) Juliette, in 2001, to the Baja California Peninsula triggered at least 419 landslides. Most of the landslides were shallow slips and debris slides of limited areal extent, which were converted rapidly into debris flows to be exported quickly out of the mountain areas towards the lowlands. Main factors affecting landslide occurrence were total storm rainfall and intensity, aspect, geology and vegetation association. Two processes can be distinguished as initiating slope failure. Accumulation of rainfall from exposed bedrock slopes, generating excess overland flow, was the main process linked to failures in 184 J. L. Antinao and L. M. Farfán concave topography. A combination of wind and excess overland flow in the more convex or planar upper slopes was a secondary process related to heterogeneity of vegetation associations in the oak-dry tropical forests ecotone, as uprooted trees dislodged large regolith and bedrock blocks, priming hillslopes for further runoff concentration. An estimative threshold curve for triggering landslides in this region is sk...

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Section: Threshold Of Slope Failurementioning

confidence: 99%

Occurrence of landslides during the approach of tropical cyclone Juliette (2001) to Baja California Sur, Mexico

Antinao¹,

Farfán²

2013

Atmósfera

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“…As a result, a failure surface develops within the soil profile or at the contact with the underlying bedrock. Through a transformation that can be due to liquefaction and dilatancy (Ellen and Fleming, 1987) the slipped mass evolve in a debris flow, that propagates downward eroding transport channels and increasing the volume of moving mass (Ellen, 1988, Crosta, 1998Wieczorek et al, 2000). Factors controlling the occurrence and distribution of shallow landslides can be divided into two categories (Wu and Sidle, 1995): the almost-static variables and the dynamic variables.…”

Section: Introductionmentioning

confidence: 99%

Distributed modelling of shallow landslides triggered by intense rainfall

Crosta

Frattini

2003

Nat. Hazards Earth Syst. Sci.

317

175

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Abstract. Hazard assessment of shallow landslides represents an important aspect of land management in mountainous areas. Among all the methods proposed in the literature, physically based methods are the only ones that explicitly includes the dynamic factors that control landslide triggering (rainfall pattern, land-use). For this reason, they allow forecasting both the temporal and the spatial distribution of shallow landslides. Physically based methods for shallow landslides are based on the coupling of the infinite slope stability analysis with hydrological models. Three different gridbased distributed hydrological models are presented in this paper: a steady state model, a transient "piston-flow" wetting front model, and a transient diffusive model. A comparative test of these models was performed to simulate landslide occurred during a rainfall event (27-28 June 1997) that triggered hundreds of shallow landslides within Lecco province (central Southern Alps, Italy). In order to test the potential for a completely distributed model for rainfall-triggered landslides, radar detected rainfall intensity has been used. A new procedure for quantitative evaluation of distributed model performance is presented and used in this paper. The diffusive model results in the best model for the simulation of shallow landslide triggering after a rainfall event like the one that we have analysed. Finally, radar

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“…For shallow landslide events, various authors analyse different time intervals to quantify the rainfall prior to a rainstorm: 3 days (Dahal and Hasegawa, 2008), 5 days (Wieczorek et al, 2000), 10 days (Crozier, 1999;Glade at al., 2000), 15 days (Aleotti, 2004), or 25 days (Terlien, 1998). In order to correlate the rainstorms triggering shallow landslides with antecedent rainfall in the study area, the cumulative rainfall at time intervals of 3, 7, 15, and 30 days was analysed and compared with the rainstorm features.…”

Section: Effect Of Antecedent Rainfallmentioning

confidence: 99%

Critical rainfall thresholds for triggering shallow landslides in the Serchio River Valley (Tuscany, Italy)

Giannecchini

Galanti

Avanzi

2012

Nat. Hazards Earth Syst. Sci.

120

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Abstract. The Serchio River Valley, in north-western Tuscany, is a well-known tourism area between the Apuan Alps and the Apennines. This area is frequently hit by heavy rainfall, which often triggers shallow landslides, debris flows and debris torrents, sometimes causing damage and death. The assessment of the rainfall thresholds for the initiation of shallow landslides is very important in order to improve forecasting and to arrange efficient alarm systems.With the aim of defining the critical rainfall thresholds for the Middle Serchio River Valley, a detailed analysis of the main rainstorm events was carried out. The hourly rainfall recorded by three rain gauges in the 1935-2010 interval was analysed and compared with the occurrence of shallow landslides. The rainfall thresholds were defined in terms of mean intensity I , rainfall duration D, and normalized using the mean annual precipitation. Some attempts were also carried out to analyze the role of rainfall prior to the damaging events. Finally, the rainfall threshold curves obtained for the study area were compared with the local, regional and global curves proposed by various authors. The results of this analysis suggest that in the study area landslide activity initiation requires a higher amount of rainfall and greater intensity than elsewhere.

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Debris-flow hazards in the Blue Ridge of central Virginia

Cited by 132 publications

References 0 publications

Occurrence of landslides during the approach of tropical cyclone Juliette (2001) to Baja California Sur, Mexico

Occurrence of landslides during the approach of tropical cyclone Juliette (2001) to Baja California Sur, Mexico

Distributed modelling of shallow landslides triggered by intense rainfall

Critical rainfall thresholds for triggering shallow landslides in the Serchio River Valley (Tuscany, Italy)

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