Magnitude estimation of a landslide-triggered debris flow in the Serra do Mar Mountain Range, Brazil

2020 ◽  
Author(s):  
Victor Carvalho Cabral ◽  
Fernando Mazo D'Affonseca ◽  
Marcelo Fischer Gramani ◽  
Agostinho Tadashi Ogura ◽  
Claudia Santos Corrêa ◽  
...  
Keyword(s):  
Debris Flow ◽  
Magnitude Estimation ◽  
Cross Sections ◽  
Debris Flows ◽  
Mountain Range ◽  
Serra Do Mar ◽  
Solids Concentration ◽  
Geomorphic Features ◽  
Total Magnitude ◽  
Future Events

<p><span>Debris flows represent great hazard to communities and infrastructures, since they move quickly and are very destructive. In Brazil, debris flows mainly occur in the Serra do Mar Mountain Range, where thousands of casualties were reported in the last two decades due to these phenomena. This study aims at estimating the magnitude of a debris-flow event that occurred in Serra do Mar on February 2017, at the Pedra Branca watershed in the State of Paraná. Debris-flow magnitude refers to the volume of material discharged during an event and is an important aspect of debris-flow hazard assessment. The Pedra Branca event was initiated by rainfall-triggered shallow landslides, damaging local oil pipelines and farms. The magnitude estimation is based on the combination of empirically based equations and the geomorphic features of the debris flow, acquired from <em>in situ</em> and aerial investigation. 28 cross-sections were made along the river channel, considering post-event channel width, erosion and accumulation depth, as well as depositional features. Sediment sources and accumulation areas were identified and delimitated based on high-resolution (1:500) aerial drone photographs. The results indicate that the landslides that initiated the event released approximately 26,884.5 m<sup>3</sup> of sediments (V<sub>i</sub>) into the main channel of Pedra Branca and that the volume eroded (V<sub>e</sub>) and accumulated (V<sub>d</sub>) along the channel are, respectively, 82,439 m<sup>3</sup> and 22,012 m<sup>3</sup>. The estimated total solids volume (V<sub>s</sub>) is 87,274 m<sup>3</sup>, assuming that V<sub>s</sub> = V<sub>i</sub> + V<sub>e</sub> - V<sub>d</sub>. Moreover, considering a solids concentration of 57% calculated according to empirically-based equations for Serra do Mar, the debris flow had a total magnitude of 153,113 m<sup>3</sup>. These estimations suggest that the February 2017 debris flow mobilised great volume of material and that 15% of the total volume accumulated on the channel bed, which can be remobilised by future events. Further research on debris-flow dynamics and recurrence at the Serra do Mar Mountain Range is recommended to mitigate future hazards.</span></p>

scholarly journals Characterization of a landslide-triggered debris flow at a rainforest-covered mountain region in Brazil

2021 ◽  
Author(s):  
Victor Carvalho Cabral ◽  
Fábio Augusto Gomes Vieira Reis ◽  
Fernando Mazo D’Affonseca ◽  
Ana Lucía ◽  
Claudia Vanessa dos Santos Corrêa ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Rain Gauge ◽  
Peak Discharge ◽  
Hazard Management ◽  
Magnitude Comparison ◽  
Tropical Regions ◽  
Serra Do Mar ◽  
Total Magnitude

AbstractDebris flows represent great hazard to humans due to their high destructive power. Understanding their hydrogeomorphic dynamics is fundamental in hazard assessment studies, especially in subtropical and tropical regions where debris flows have scarcely been studied when compared to other mass-wasting processes. Thus, this study aims at systematically analyzing the meteorological and geomorphological factors that characterize a landslide-triggered debris flow at the Pedra Branca catchment (Serra do Mar, Brazil), to quantify the debris flow’s magnitude, peak discharge and velocity. A magnitude comparison with empirical equations (Italian Alps, Taiwan, Serra do Mar) is also conducted. The meteorological analysis is based on satellite data and rain gauge measurements, while the geomorphological characterization is based on terrestrial and aerial investigations, with high spatial resolution. The results indicate that it was a large-sized stony debris flow, with a total magnitude of 120,195 m3, a peak discharge of 2146.7 m3 s−1 and a peak velocity of 26.5 m s−1. The debris flow was triggered by a 188-mm rainfall in 3 h (maximum intensity of 128 mm h−1), with an estimated return period of 15 to 20 years, which, combined with the intense accumulation of on-channel debris (ca. 37,000 m3), indicates that new high-magnitude debris flows in the catchment and the region are likely to occur within the next two decades. The knowledge of the potential frequency and magnitude (F–M) can support the creation of F–M relationships for Serra do Mar, a prerequisite for reliable hazard management and monitoring programs.

scholarly journals Debris-flow activity in five adjacent gullies in a limestone mountain range

2015 ◽  
Vol 42 (1) ◽  
Author(s):  
Klaus Schraml ◽  
Markus Oismüller ◽  
Markus Stoffel ◽  
Johannes Hübl ◽  
Roland Kaitna
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
National Park ◽  
Regional Scale ◽  
Field Investigation ◽  
Mountain Range ◽  
Sediment Sources ◽  
Aerial Vehicle ◽  
Flow Activity ◽  
Local Variability

Abstract Debris-flows are infrequent geomorphic phenomena that shape steep valleys and can repre-sent a severe hazard for human settlements and infrastructure. In this study, a debris-flow event chro-nology has been derived at the regional scale within the Gesäuse National Park (Styria, Austria) using dendrogeomorphic techniques. Sediment sources and deposition areas were mapped by combined field investigation and aerial photography using an Unmanned Aerial Vehicle (UAV). Through the analysis of 384 trees, a total of 47 debris-flows occurring in 19 years between AD 1903 and 2008 were identified in five adjacent gullies. Our results highlight the local variability of debris-flow activi-ty as a result of local thunderstorms and the variable availability of sediment sources.

Post-earthquake changes in debris flow susceptibility in the Upper Minjiang catchment (Sichuan, China), as revealed by meteorological and hydro-meteorological thresholds

2020 ◽  
Author(s):  
Roberto Greco ◽  
Pasquale Marino ◽  
Siva Srikrishnan ◽  
Xuanmei Fan
Keyword(s):  
Water Balance ◽  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Strong Increase ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
2008 Wenchuan Earthquake ◽  
Soil Storage ◽  
Triggering Rainfall

<p>On May 12, 2008, a Mw 7.9 earthquake struck Wenchuan, Longmen Shan Area, in western Sichuan, China, at the eastern margin of the Tibetan Plateau. This earthquake was the largest and most destructive event in the last 60 years, causing more than 87000 casualties. The economic loss was estimated at some 1100 billion RMB. The major fault rupture produced surface displacements up to 3-4 meters, spreading from the epicenter (near the town of Yingxiu) for 240 km along the mountain range.</p><p>The Wenchuan Earthquake triggered almost 200000 co-seismic landslides over a region larger than 110000 km<sup>2</sup>, leading to the accumulation of large volumes of loose material either along slopes or in gullies. After the earthquake, this material caused a strong increase of debris flow occurrence in the subsequent years, mainly in the worst-hit areas, such as Wenchuan, Beichuan and Mao counties. During the years immediately after the earthquake, the rainfall required for debris flow triggering resulted clearly smaller than before (Guo et al., 2016). Afterwards, the response of the debris deposits to rainfall changed, leading to a general recovery of stability and a reduction of debris flow frequency and magnitude (Domènech et al., 2019).</p><p>In this study, the assessment of debris flows occurrence throughout upper Minjiang catchment, to which Wenchuan county belongs, is modeled with two empirical approaches, both based on the available record of precipitations and debris flows in the years 2008-2015. In the first approach, a threshold to predict debris flow occurrence is defined based on intensity and duration of potentially triggering rainfall events (meteorological threshold). With the second approach, also the hydrological conditions predisposing the slopes to debris flows are considered, by assessing the water balance in the catchment with a simplified lumped hydrological model, based on the Budyko framework (Zhang et al., 2008), and defining a threshold to predict debris flows based on rainfall depth and estimated soil storage prior the onset of rainfall (hydro-meteorological threshold).</p><p>The obtained results indicate that the hydro-meteorological threshold allows catching the progressive recovery of stability of the debris deposits much better than the meteorological threshold, leading to identification of increasing thresholds, both in terms of pre-event soil storage and triggering rainfall amount, in the years from 2008 onward. Such a result shows that the adoption of process-based approaches , even empirical and strongly simplified as in the presented case, leads to predictions of debris flow occurrence more robust than those based solely on rainfall information.</p><p> </p><p>References</p><p>Domènech, G., Fan, X., Scaringi, G., van Asch, T.W.J., Xu, Q., Huang, R., Hales, T.C., 2019. Modelling the role of material depletion, grain coarsening and revegetation in debris flow occurrences after the 2008 Wenchuan earthquake. Eng. Geol. 250, 34-44.</p><p>Guo, X., Cui, P., Li, Y., Fan, J., Yan, Y., Ge, Y., 2016. Temporal differentiation of rainfall thresholds for debris flows in Wenchuan earthquake-affected areas. Environ. Earth Sci. 75, 1–12.</p><p>Zhang, L., Potter, N., Hickel, K., Zhang, Y., Shao, Q., 2008. Water balance modeling over variable time scales based on the Budyko framework – Model development and testing. J. Hydrol. 360, 117-131.</p>

scholarly journals The December 2012 Mayo River debris flow triggered by Super Typhoon Bopha in Mindanao, Philippines: lessons learned and questions raised

2016 ◽  
Vol 16 (12) ◽  
pp. 2683-2695 ◽  
Author(s):  
Kelvin S. Rodolfo ◽  
A. Mahar F. Lagmay ◽  
Rodrigo C. Eco ◽  
Tatum Miko L. Herrero ◽  
Jerico E. Mendoza ◽  
...  
Keyword(s):  
Climate Change ◽  
Debris Flow ◽  
Population Growth ◽  
Debris Flows ◽  
Lessons Learned ◽  
Loss Of Life ◽  
River Watershed ◽  
Super Typhoon ◽  
Future Events ◽  
The Village

Abstract. Category 5 Super Typhoon Bopha, the world's worst storm of 2012, formed abnormally close to the Equator, and its landfall on Mindanao set the record proximity to the Equator for its category. Its torrential rains generated an enormous debris flow in the Mayo River watershed that swept away much of the village Andap in the New Bataan municipality, burying areas under rubble as thick as 9 m and killing 566 people. Established in 1968, New Bataan had never experienced super typhoons and debris flows. This unfamiliarity compounded the death and damage. We describe Bopha's history, debris flows and the Mayo River disaster, and then we discuss how population growth contributed to the catastrophe, as well as the possibility that climate change may render other near-Equatorial areas vulnerable to hazards brought on by similar typhoons. Finally, we recommend measures to minimize the loss of life and damage to property from similar future events.

scholarly journals The December 2012 Mayo River debris flow triggered by Super Typhoon Bopha in Mindanao, Philippines: Lessons learned and questions raised

2016 ◽  
Author(s):  
Kelvin S. Rodolfo ◽  
A. Mahar F. Lagmay ◽  
R. Narod Eco ◽  
Tatum Miko L. Herrero ◽  
Jerico E. Mendoza ◽  
...  
Keyword(s):  
Climate Change ◽  
Debris Flow ◽  
Population Growth ◽  
Debris Flows ◽  
Lessons Learned ◽  
Loss Of Life ◽  
River Watershed ◽  
Super Typhoon ◽  
Future Events

Abstract. Category 5 Super Typhoon Bopha, the world's worst storm of 2012, formed abnormally close to the Equator, and its landfall on Mindanao set the record proximity to the Equator for its category. Its torrential rains generated an enormous debris flow in the Mayo River watershed that swept away much of Andap village in New Bataan municipality, burying areas under rubble as thick as 9 meters and killing 566 people. Established in 1968, New Bataan had never experienced super typhoons and debris flows. This unfamiliarity compounded the death and damage. We describe Bopha's history, debris flows and the Mayo River disaster, then discuss how population growth contributed to the catastrophe, and the possibility that climate change may render other near-Equatorial areas vulnerable to hazards brought by similar typhoons. Finally, we recommend measures to minimize the loss of life and damage to property from similar, future events.

scholarly journals The mechanism of landslide-induced debris flow in Geothermal area, Bukit Barisan Mountains of Sumatra, Indonesia

2021 ◽  
Author(s):  
Wahyu Wilopo ◽  
Teuku Faisal Fathani
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Volcanic Rocks ◽  
Thick Layer ◽  
Source Area ◽  
Site Investigation ◽  
Xrd Analysis ◽  
Alluvial Fan ◽  
Mountain Range ◽  
Geothermal Area

Landslides frequently occur in Indonesia, especially in the geothermal areas located on Sumatra's mountainous island. On April 28, 2016, around 04:30 Western Indonesia Time, a landslide-induced debris flow occurred in Lebong District, Bengkulu Province, Indonesia. The source area of the landslide was located at Beriti Hill on the Bukit Barisan Mountain Range. It resulted in 6 fatalities and damage to infrastructures such as geothermal facilities, roads, water pipes, houses, and bridges. Subsequent landslides and debris flows occurred on April 30, May 2, and 3, 2016. Therefore, this study aims to examine the mechanism and to know the most significant contributing factor to the Beriti Hill landslide. Site investigation, soil sampling, XRD analysis, and Lidar analysis were carried out in the research. Beriti Hill is a geothermal area with many manifestations and is composed of volcanic rocks. Alteration processes produced a thick layer of soil from volcanic rocks. The thick soil dominated by clay minerals and steep slopes is the dominant controlling factor of a landslide, triggered by high rainfall intensity. Debris flows are recurring events based on the Air Kotok river's stratigraphic data downstream of the landslide area. The debris flow material is toxic due to the low pH from the geothermal process. Therefore, the alluvial fan deposit area from Beriti Hill debris flow is a hazard zone and unsuitable for settlement and agriculture.

WHAT CAN WE LEARN FROM SEISMIC RECORDINGS OF DEBRIS FLOWS? PRELIMINARY FINDINGS FROM LARGE SCALE SEISMIC EXPERIMENTS AT THE USGS DEBRIS-FLOW FLUME

2016 ◽  
Author(s):  
Kate E. Allstadt ◽  
◽  
Maxime Farin ◽  
Jason W. Kean ◽  
Richard M. Iverson ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Large Scale

scholarly journals Learning Case Study of a Shallow-Water Model to Assess an Early-Warning System for Fast Alpine Muddy-Debris-Flow

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 750
Author(s):  
Antonio Pasculli ◽  
Jacopo Cinosi ◽  
Laura Turconi ◽  
Nicola Sciarra
Keyword(s):  
Debris Flow ◽  
Shallow Water ◽  
Early Warning ◽  
Debris Flows ◽  
Early Warning System ◽  
Warning System ◽  
Extreme Weather Events ◽  
Water Model ◽  
Computational Time ◽  
Processing Unit

The current climate change could lead to an intensification of extreme weather events, such as sudden floods and fast flowing debris flows. Accordingly, the availability of an early-warning device system, based on hydrological data and on both accurate and very fast running mathematical-numerical models, would be not only desirable, but also necessary in areas of particular hazard. To this purpose, the 2D Riemann–Godunov shallow-water approach, solved in parallel on a Graphical-Processing-Unit (GPU) (able to drastically reduce calculation time) and implemented with the RiverFlow2D code (version 2017), was selected as a possible tool to be applied within the Alpine contexts. Moreover, it was also necessary to identify a prototype of an actual rainfall monitoring network and an actual debris-flow event, beside the acquisition of an accurate numerical description of the topography. The Marderello’s basin (Alps, Turin, Italy), described by a 5 × 5 m Digital Terrain Model (DTM), equipped with five rain-gauges and one hydrometer and the muddy debris flow event that was monitored on 22 July 2016, were identified as a typical test case, well representative of mountain contexts and the phenomena under study. Several parametric analyses, also including selected infiltration modelling, were carried out in order to individuate the best numerical values fitting the measured data. Different rheological options, such as Coulomb-Turbulent-Yield and others, were tested. Moreover, some useful general suggestions, regarding the improvement of the adopted mathematical modelling, were acquired. The rapidity of the computational time due to the application of the GPU and the comparison between experimental data and numerical results, regarding both the arrival time and the height of the debris wave, clearly show that the selected approaches and methodology can be considered suitable and accurate tools to be included in an early-warning system, based at least on simple acoustic and/or light alarms that can allow rapid evacuation, for fast flowing debris flows.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

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