521 Works

Monitoring of rainfall and soil moisture at the Rebaixader catchment (Central Pyrenees)

Marcel Hürlimann, Raül Oorthuis, Clàudia Abancó, Luigi Carleo & José Moya
The instrumental monitoring of torrential catchments is a fundamental research task and provides necessary information to improve our understanding on the mechanisms of debris flows. While most monitoring sites include meteorological sensors and analyze the critical rainfall conditions, only very few contain soil moisture measurements. In our monitoring site, the Rebaixader catchment, 11 debris flows and 24 debris floods were detected during the last nine years. Herein, the initiation mechanisms of these torrential flows were...

Implementation of an integrated management strategy to deal with landslide triggered debris flows: the Valloire case study (Savoie, France)

Dominique Laigle, Denis Jongmans, Frédéric Liebault, Laurent Baillet, Etienne Rey, Firmin Fontaine, Laurent Borgniet, Mylène Bonnefoy-Demongeot & Frédéric Ousset
The Rieu Benoît is a debris-flow-prone catchment located in Valloire (Savoie, France). In 2011, a lateral landslide was detected about 600 m upstream of the fan apex where houses are present. This landslide has evolved slowly since 2011 but is likely, in case of rapid collapse, to provide up to 150,000 to 200,000 m3 of material to the channel and generate intense debris flows thus threatening human settlements on the fan and in the Valloire...

Measurements of velocity profiles in natural debris flows: a view behind the muddy curtain

Georg Nagl, Johannes Huebl & Roland Kaitna
The internal deformation behavior of natural debris flows is of interest for model development and model testing for debris-flow hazard mitigation. Up to now, only a view attempts were made to measure velocity profiles in natural debris flows due to low predictability and high destructive power of these flows. In this contribution we present recent advances of measuring in-situ velocity profiles together with flow parameters like flow depth, basal normal stress, and pore fluid pressure....

Impact of global warming on the formation of debris flows in an alpine region of southeastern Tibet, The

Peng Cui, Yang Jia & Dingzhu Liu
Debris flows are one of the typical mountain hazards in the Qinghai Tibet Plateau, and they are also one of the most active and harmful hazards in the southeast of Tibet. Different from the formation mechanism of debris-flow hazard at low altitude, the debris flows in this alpine region are caused by the coupling of glacier movement, snow melting, and precipitation. To get the meteorological conditions in formation area of debris flows at the time...

Complexity of a debris-flow system at Forest Falls, California

Kerry Cato & Brett Goforth
Historical patterns of debris flows have been reconstructed at the town of Forest Falls in the San Bernardino Mountains using a variety of field methods (mapping flow events after occurrence, dendrochronology evidence, soil chrono sequences). Large flow events occur when summer thunderstorms produce brief high-intensity rainfall to mobilize debris, however the geomorphic system exhibits properties of non-linear response rather than being a single-event precipitation-driven process. Previous studies contrasted the relative water content of flows generated...

Correlation between the slump parameters and rheological parameters of debris-flow

Chyan-Deng Jan, Chih-Yuan Yang, Ciao-Kai Hsu & Litan Dey
Rheological characteristics are important information for understanding or simulating debris-flow movement. Debris-flow movements involves complex and heterogeneous material with grain size distributions ranging from silt to large rocks. Conventional rheometers are usually limited to measure the rheological parameters of debris-flow of fine particles. Slump-tests has been used to evaluate the flow behaviour of fresh concretes which allow the tested concrete slurries to have larger particles. In this study, the relationship between the parameters obtained from...

Hydro-meteorological trigger conditions of debris flows in Austria

Roland Kaitna, David Prenner, Martin Braun & Markus Hrachowitz
Different factors influence the disposition of a watershed for initiation of debris flows, including meteorological trigger conditions as well as the hydrologic and geomorphic disposition. The latter includes slowly changing factors like relief energy or sediment availability, whereas the hydrologic state of a watershed may vary over short time scales. This contribution summarizes the outcomes of a long term project to quantify meteorological and hydrological trigger conditions leading to debris flows at different temporal and...

Debris-flow initiation promoted by extension of a slow-moving landslide

Mark E. Reid & Dianne L. Brien
The dynamics of slow landslide motion can predispose oversteepened and extended slide regions to debris-flow initiation. For more than 20 years, our real-time monitoring, combined with repeat high-precision GPS surveys, of the Cleveland Corral landslide complex, California, USA, reveals that debris flows initiate from slow-moving kinematic elements of this complex. Different slide elements move in different wet years, and all remain dormant in dry years. To explore controls on landslide- element kinematics, we use triaxial...

4000-year history of debris flows in north-central Washington State, USA: preliminary results from trenching and surficial geologic mapping at the Pope Creek fan

Jeffrey A. Coe, Erin K. Bessette-Kirton, Stephen L. Slaughter, Francis K. Rengers, Trevor A. Contreras, Katherine A. Mickelson, Emily M. Taylor, Jason W. Kean, Kara E. Jacobacci & Molly A. Hanson
Long-term records of the magnitude and frequency of debris flows on fans are rare, but such records provide critical information needed for debris-flow hazard and risk assessments. This study explores the history of debris flows on a fan with seasonally inhabited cabins at Pope Creek along the Entiat River about 48 km upstream from the town of Entiat, Washington. Motivation for this study was provided by the Duncan Fire, a wildfire which burned the Pope...

Thermal transport: conduction and radiation: a module developed for hands-on learning

Connor Pierce, Portia J. Allen, George Smith, Reuben T. Collins, Carolyn A. Koh, Barbara M. Moskal & Meenakshi Singh
This document is a lesson plan for a short module covering: (i) the concept of temperature and how it is measured, (ii) the transportation of heat - specifically conduction and radiation, (iii) the material dependence of the transportation of heat. Colorado state science standards addressed by the module are included. The module is readily adapted for students in grades 1-12. It was originally drafted for presentation to children aged 7-13 at the Rocky Mountain Camp...

Morphology of debris flow deposits from a 1967 event in Caraguatatuba, Serra do Mar, Brazil, The

Vivian Cristina Dias, Tiago Damas Martins, Marcelo Fischer Gramani, Rebeca Durço Coelho, Helen Cristina Dias & Bianca Carvalho Vieira
Morphological characteristics of debris-flow deposits are a fundamental part of the field study of the process. The deposits show aspects related to flow dynamics, which reflects its main mechanics and enables the correct identification of process. Occurrences of debris flows are quite common in Brazil, especially in the Serra do Mar region, located at the southern/southeastern coast of the country. Geological and geomorphological characteristics and high rainfall indexes contribute to high susceptibility of the process...

Method for predicting debris-flow occurrence based on a rainfall and sediment runoff model, A

Masaharu Fujita, Kazuki Yamanoi & Gohta Suzuki
Based on a basin scale rainfall runoff model, we proposed a prediction method of debris-flow occurrence on steep mountain slopes related to hydrological processes such as the rainfall infiltration, the surface flow and the slope stability. For example, in one case that the soil layer is unsaturated and a landslide does not occur in the slope even though the groundwater level rises in the slope soil layer during a rainfall event, it is unlikely for...

Rainfall intensity limitation and sediment supply independence of post-wildfire debris flows in the western U.S.

Paul M. Santi & Blaire MacAulay
This work explores two hypotheses related to post-wildfire debris flows: first, that they are rainstorm-intensity limited and not rainstorm-volume limited, and second, that they are not sediment-supply limited. The first hypothesis suggests that it is common to generate more than enough water to account for the volume in the debris flow, but to actually produce a debris flow the water must be delivered in sufficiently large doses. This is demonstrated by a dataset of 44...

Relationship between rainfall intensity and debris-flow initiation in a southern Colorado burned area

Evan Q. Friedman & Paul M. Santi
Wildfire impacts on vegetation, soils, and resulting hydrologic processes often result in debris-flow activity in mountainous areas, particularly in response to intense rainfall events that follow. Rainfall thresholds for debris-flow initiation in burned areas have been studied in a variety of settings. It has been proposed that short duration, high-intensity rainfall events are responsible for debris-flow initiation in burned areas. The timing of these responses relative to rainfall intensity peaks is not well understood, leaving...

Regional level debris-flow hazard assessment for alpine infrastructure facilities using the 3D numerical high-performance simulation tool FIMT

Manfred Scheikl & David Powell
Alpine infrastructure such as roads, railways, pipelines, powerlines and hydropower facilities, as well as alpine communities, are exposed to debris-flow hazards, rock-fall and snow avalanches. In most cases, debris-flows are rainfall induced and affect large areas, causing substantial financial and individual damages. Austrian infrastructure owners are maintaining approximately 5,000 km of railway tracks and at least 1,000 km of high priority highways which are exposed to debris-flow hazards. For assessing potential debris-flow impact along these...

Modeling frequent debris flows to design mitigation alternatives

Joanna Crowe Curran & Pat Flanagan
Debris flows are a common problem in Western Washington State. One persistent location of debris flows is Slide Ridge. Glacial till deposits erode in debris flows which travel to Lake Chelan, passing through the community of Shrine Beach in Washington State. In the early 1990s an unlined debris channel was constructed from the apex of Slide Ridge to Chelan lake and a large debris basin was constructed on the upslope side of the road crossing....

Using satellite radar interferometry to delineate burn area and detect sediment accumulation, 2018 Montecito disaster, California

Danielle Smilovsky & Jeffrey R. Keaton
The Thomas Fire burned slopes above Montecito, California in December 2017, setting the stage for debris flows and flash floods in response to precipitation that exceeded a threshold intensity and duration. A narrow cold frontal rainband storm occurred on January 9, 2018, that exceeded the threshold and caused a disaster in Montecito, killing 23 people, injuring many others, destroying residential buildings, and community infrastructure. The Geotechnical Extreme Event Reconnaissance (GEER) Association mobilized a team to...

Flume investigation of the interaction mechanisms between debris flow and slit dams

H. S. Hu, Gordon G.D. Zhou & Dongri Song
Slit dams are designed to mitigate debris-flow hazards. However, according to field surveys and past experimental studies, slit dams constructed using currently prescribed design methods usually become blocked, which then leads to the loss of capacities of the slit dam’s capability to mitigate debris-flow hazards. In this study, a series of flume tests were conducted to investigate the interaction mechanisms between debris flows and slit dams. This work aims to contribute to the design of...

Monitoring and early warning of debris-flow in an earthquake impacted area, Baishahe catchment, southwest China

Hongling Tian, Zongji Yang, Jianping Qiao & Lili Shi
After 10 years of the Wenchuan earthquake of China, the post-seismic landslides are turning weak. However, the debris flows in earthquake-stricken area continue to be threat. In order to reduce the risk from debris flows in this region, we discuss the operation of an alert system, monitoring objectives, and early-warning policies. Three gullies in the Baishahe catchment, Dujiangyan, Southwest China were selected and rain-gauge, tilt-sensor, mud-meter and ground acoustic meter combined to a warning system...

Comparison of an empirical and a process-based model for simulating debris-flow inundation following the 2010 Schultz Fire in Coconino County, Arizona, USA

Ann M. Youberg & Luke A. McGuire
The importance of understanding the extent of areas threatened by post-wildfire debris flows cannot be overstated, as illustrated by the post-Thomas Fire flows through Montecito, California, in January 2018. Methods and models developed by the U.S. Geological Survey to identify burned basins at risk of producing post-wildfire debris flows are well established, effective and commonly used. In contrast, there is no similarly established methodology for delineating debris-flow hazard zones downstream of basins prone to producing...

Long travel distance of landslide-induced debris flows

Yuki Nishiguchi & Taro Uchida
Large-scale landslides often induce debris flows and cause serious damage to humans. These events typically have water contents in the landslide mass less than 60% and sediment concentrations more than 40%. In spite of high sediment concentrations, landslide-induced debris flows can runout long distances. For large-scale stony debris flows, many previous studies have suggested that coarse gravels behave as a solid phase, whereas fine particles with interstitial water can behave as a fluid phase. We...

Conceptual framework for assessing disturbance impacts on debris-flow initiation thresholds across hydroclimatic settings

Benjamin B. Mirus, Dennis M. Staley, Jason W. Kean, Joel B. Smith, Rick Wooten, Luke A. McGuire & Brian A. Ebel
The destructive and deadly nature of debris flows has motivated research into empirical rainfall thresholds to provide situational awareness, inform early warning systems, and reduce loss of life and property. Disturbances such as wildfire and land-cover change can influence the hydrological processes of infiltration and runoff generation; in steep terrain this typically lowers empirical thresholds for debris-flow initiation. However, disturbance impacts, and the post-disturbance recovery may differ, depending on the severity, nature, extent, and duration...

Numerical study of debris flows in presence of obstacles and retaining structures: a case study in the Italian Alps

Marina Pirulli, Mario Manassero, Carmine Terrioti, Alessandro Leonardi & Giulia La Porta
Debris flows are one of the most frequent mass movement processes and occur in all regions with steep relief and at least occasional rainfall. Their high flow velocity, impact forces, and long runout, combined with poor temporal predictability, cause debris flows to be one of the most hazardous landslide types. An essential aspect of debris-flow risk management is the design of mitigation measures, which reduce the existing risk to an accepted level of residual risk,...

Biogenicity and biosignature potential of carbonate/silica structures in Little Hot Creek, The

Emily A. Kraus, R. Agustin Mors, Scott R. Beeler, James G. Floyd, Blake W. Stamps, Heather S. Nunn, Bradley S. Stevenson, Russel S. Shapiro, Hope Johnson, Frank A. Corsetti & John R. Spear

Highly insidious extreme phishing attacks, The

Rui Zhao, Samantha John, Stacy Karas, Cara Bussell, Jennifer Roberts, Daniel Six, Brandon Gavett & Chuan Yue

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