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

Reanalysis of Flash Floods and Debris Flows on two continents and their management strategies

2021 ◽  
Author(s):  
Juan Daniel Rios-Arboleda
Keyword(s):  
Risk Management ◽  
Developing Countries ◽  
South America ◽  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Management Strategies ◽  
Original Analysis ◽  
Risk Management Strategies ◽  
Latitudinal Patterns

<p>This research expands the original analysis of Baker and Costa (1987) including data from Europe and South America with the objective to understand if there are emerging latitudinal patterns. In addition, the threshold proposed by Zimmermann et al. (1997) it is evaluated with the data from tropical zones finding that this is a good predictor.</p><p>Mainly, recent Debris Flow occurred in South America are analyzed with the aim of identifying the best risk management strategies and their replicability for developing countries, particularly, the cases that have occurred in Colombia and Venezuela in the last 30 years are analyzed in order to compare management strategies and understand which are the most vulnerable areas to this phenomenon.</p><p>It is concluded that large-scale and multinational projects such as SED ALP are required in South America to better characterize events that have left multiple fatalities (sometimes hundreds of people) and better understand how to manage the risk on densely populated areas.</p><p>Finally, the use of amateur videos is proposed to characterize these events in nations with limited budgets for projects such as SED ALP, methodology that will be described extensively in later works.</p>

Research on Motion Characteristics and Formation Mechanism of Debris Flow

2014 ◽  
Vol 711 ◽  
pp. 388-391
Author(s):  
Ji Wei Xu ◽  
Ming Dong Zhang ◽  
Mao Sheng Zhang
Keyword(s):  
Debris Flow ◽  
Formation Mechanism ◽  
Debris Flows ◽  
Catchment Area ◽  
Large Scale ◽  
Large Range ◽  
Extreme Rainfall ◽  
Small Catchment ◽  
Rainfall Characteristics ◽  
Motion Characteristics

On July 9 2013, debris flows occurred around Longchi town with large scale and wide harm, which was a great threat to people's life and property as well as reconstruction work. Debris flow ditch in the surrounding town was studied. This paper focused on loose materials, topography and rainfall characteristics, and explored the formation mechanism of debris flow in Longchi town. The result shows that: a small catchment area in valleys also have the risk of large range of accumulation of debris flow, the debris flow is caused by a lot of loose materials in mountains after earthquake and extreme rainfall. Research results contribute to a better understanding of trigger condition of debris flow after earthquake.

scholarly journals Risk assessment of debris flow based on group decision making – A case study of Luanchuan County, Henan Province, China

2018 ◽  
Vol 175 ◽  
pp. 04025
Author(s):  
Pengyu Chen ◽  
Ying Kong
Keyword(s):  
Risk Assessment ◽  
Decision Making ◽  
Debris Flow ◽  
Group Decision Making ◽  
Debris Flows ◽  
Large Scale ◽  
Group Decision ◽  
Henan Province ◽  
Comprehensive Assessment ◽  
Material Sources

Luanchuan County, located in the mountains of Western Henan Province, is characterized by poor geological environment and abundant material sources and rainfalls. Debris flows have occurred many times in this county, and in some gully debris flows exhibit a large scale, requiring risk assessment. In the multi-factor comprehensive assessment methods for debris flow risk, it is really important to determine the weight of each factor since this affects the reliability of the assessment results. Given that the subjective weighting method can accurately reflect the importance of each factor, in order to improve the reliability of subjective weighting, the group decision making method is used to determine the weight of each factor. Group decision making is realized using the analytic hierarchy process and the data fusion algorithm. In this method, the expert combination weight is determined; on this basis, a model for comprehensive assessment of debris flow risk is established by the linear weighted sum method, and risk assessment is performed for gullies with medium to large-scale debris flows in the study area. The assessment results show that all debris flow gullies face minor to moderate risks. For gullies with high risk degree, it is suggested to timely clear material sources in channels and construct or reinforce retaining dams in order to prevent re-occurrence of debris flows.

A review of the classification of landslides of the flow type

2001 ◽  
Vol 7 (3) ◽  
pp. 221-238 ◽  
Author(s):  
Oldrich Hungr ◽  
S. G. Evans ◽  
M. J. Bovis ◽  
J. N. Hutchinson
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Debris Avalanche ◽  
Basic Material ◽  
Morphological Aspects ◽  
Flow Slides ◽  
Size Limits ◽  
Plastic Clays ◽  
Earth Flows

Abstract As a result of the widespread use of the landslide classifications of Varnes (1978), and Hutchinson (1988), certain terms describing common types of flow-like mass movements have become entrenched in the language of engineering geology. Example terms include debris flow, debris avalanche and mudslide. Here, more precise definitions of the terms are proposed, which would allow the terms to be retained with their original meanings while making their application less ambiguous. A new division of landslide materials is proposed, based on genetic and morphological aspects rather than arbitrary grain-size limits. The basic material groups include sorted materials: gravel, sand, silt, and clay, unsorted materials: debris, earth and mud, peat and rock. Definitions are proposed for relatively slow non-liquefied sand or gravel flows, extremely rapid sand, silt or debris flow slides accompanied by liquefaction, clay flow slides involving extra-sensitive clays, peat flows, slow to rapid earth flows in nonsensitive plastic clays, debris flows which occur in steep established channels or gullies, mud flows considered as cohesive debris flows, debris floods involving massive sediment transport at limited discharges, debris avalanches which occur on open hill slopes and rock avalanches formed by large scale failures of bedrock.

Hazards on Dujiangyan-Wenchuan Highways Induced by Catastrophic Debris Flows on July 10 2013 and Prevention

2014 ◽  
Vol 501-504 ◽  
pp. 2463-2472 ◽  
Author(s):  
Yong Gang Ge ◽  
Qiang Zou ◽  
Jian Qiang Zhang ◽  
Xiao Jun Guo
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Integrated Management ◽  
Gansu Province ◽  
Chain Process ◽  
Outburst Flood ◽  
Protection Measures ◽  
Traffic Security ◽  
Dangerous Section

After the Wenchuan Earthquake on May 12 2008, the highways from Dujiangyan to Wenchuan, a crucial passage from Chengdu to Sichuan Western Plateau and Gansu province, are always seriously endangered by landslides, debris flows and their following hazards. Hundreds of debris flows from watersheds, gullies and slopes on July 10 2013 produced fatal hazards and destruction on the Highway G213 and the Express Highway from Yingxiu to Wenchuan. The debris flows are characterized by numerous-occurrence, large flux (645~2238m3/s) and large magnitude (5~126×104m3) as well as the hazard chain process which is composed of debris flow, dammed lake and outburst flood. The highways were seriously destructed and blocked in 16 sites, which were induced by 6 collapsed bridges, 3 submerged bridges, 3 buried tunnel entrances, 1 site collapsed highway base and 7 sites buried highway base or bridges, and the traffic was completely interrupted. Based on analyzing the destruction modes of highways, it was found that the large-scale and potential debris flows and the irrational location of some sections, vulnerable protection measures and low resistant capability of highways against debris flows were responsible for huge highway destructions. Considering the active debris flows in the future at least 5~10 years, it was strongly suggested that potential debris flow identification, integrated management of disastrous watershed, dangerous road line altering, increasing and strengthening protection constructions at dangerous section and improving highway reconstruction standard should be carried out for highway protection and traffic security.

scholarly journals Atmospheric Forcing of Debris Flows in the Southern Swiss Alps

2013 ◽  
Vol 52 (7) ◽  
pp. 1554-1560 ◽  
Author(s):  
Andrea Toreti ◽  
Michelle Schneuwly-Bollschweiler ◽  
Markus Stoffel ◽  
Jürg Luterbacher
Keyword(s):  
Time Series ◽  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Reanalysis Data ◽  
Swiss Alps ◽  
Classification Algorithms ◽  
Precipitation Series ◽  
Large Scale Circulation

AbstractThis article addresses the role of large-scale circulation and thermodynamical features in the release of past debris flows in the Swiss Alps by using classification algorithms, potential instability, and convective time scale. The study is based on a uniquely dense dendrogeomorphic time series of debris flows covering the period 1872–2008, reanalysis data, instrumental time series, and gridded hourly precipitation series (1992–2006) over the area. Results highlight the crucial role of synoptic and mesoscale forcing as well as of convective equilibrium on triggering rainfalls. Two midtropospheric synoptic patterns favor anomalous southwesterly flow toward the area and high potential instability. These findings imply a certain degree of predictability of debris-flow events and can therefore be used to improve existing alert systems.

scholarly journals Contribution of Excessive Supply of Solid Material to a Runoff-Generated Debris Flow during Its Routing Along a Gully and Its Impact on the Downstream Village with Blockage Effects

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 169 ◽  
Author(s):  
Ming-liang Chen ◽  
Xing-nian Liu ◽  
Xie-kang Wang ◽  
Tao Zhao ◽  
Jia-wen Zhou
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Residential Buildings ◽  
Solid Material ◽  
Sediment Supply ◽  
Mitigation Measures ◽  
Dry Land ◽  
Field Investigations ◽  
Abundant Supply

On 8 August 2017, a runoff-generated debris flow occurred in the Puge County, Sichuan Province of southwestern China and caused huge property damage and casualties (25 people died and 5 people were injured). Emergency field investigations found that paddy fields, dry land, residential buildings and roads suffered different degrees of impact from the debris flow. This paper reveals the formation process of the debris flow by analyzing the characteristics of rainfall precipitation and sediment supply conditions in the study area and it approaches the practical application of hazard prevention and mitigation constructions. Doppler weather radar analysis indicates that a very high intensity rainfall occurred in the middle and upper zones of the basin, illustrating the importance of enhancing rainfall monitoring in high-altitude areas. The abundant supply of deposits in gully channels is among the significant causes of a transformation from mountain floods to large-scale debris flows. It was also found that the two culverts played an important role in the movement affecting the processes of debris flows which has substantially aggravated the destructive outcome. The excessive supply of solid material and local blockage with outburst along a gully must receive significant attention for the prediction of future debris flows, hazard prevention and mitigation measures.

scholarly journals Application of simulation technique on debris flow hazard zone delineation: a case study in the Daniao tribe, Eastern Taiwan

2011 ◽  
Vol 11 (11) ◽  
pp. 3053-3062 ◽  
Author(s):  
M. P. Tsai ◽  
Y. C. Hsu ◽  
H. C. Li ◽  
H. M. Shu ◽  
K. F. Liu
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Sensitivity Factor ◽  
Original Design ◽  
Initial Volume ◽  
Front Position ◽  
Landslides And Debris Flows ◽  
Numerical Program

Abstract. Typhoon Morakot struck Taiwan in August 2009 and induced considerable disasters, including large-scale landslides and debris flows. One of these debris flows was experienced by the Daniao tribe in Taitung, Eastern Taiwan. The volume was in excess of 500 000 m3, which was substantially larger than the original design mitigation capacity. This study considered large-scale debris flow simulations in various volumes at the same area by using the DEBRIS-2D numerical program. The program uses the generalized Julien and Lan (1991) rheological model to simulate debris flows. In this paper, the sensitivity factor considered on the debris flow spreading is the amount of the debris flow initial volume. These simulated results in various amounts of debris flow initial volume demonstrated that maximal depths of debris flows were almost deposited in the same area, and also revealed that a 20% variation in estimating the amount of total volume at this particular site results in a 2.75% variation on the final front position. Because of the limited watershed terrain, the hazard zones of debris flows were not expanded. Therefore, the amount of the debris flow initial volume was not sensitive.

Quantitative analysis of the debris flow risk to concentrated rural settlement in southwest Sichuan, China

2021 ◽  
Author(s):  
Li Wei ◽  
Kaiheng Hu
Keyword(s):  
High Risk ◽  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Sichuan Province ◽  
Horizontal Distance ◽  
Rural Settlements ◽  
Residential Areas ◽  
Planning Stage ◽  
Societal Risk

<p><strong>Sichuan Province in southwest China is highly susceptible to debris flow disasters and suffers much damage to buildings and loss of human lives in concentrated rural settlements each year</strong><strong>.</strong><strong> By combining geographic information system (GIS) and Deep Encoding Network (DE-Net) methods, we proposed an automatic identification method for buildings highly susceptible to debris flows with large-scale digital elevation data and high-resolution remote sensing imagery based on a vulnerability matrix containing different threshold values of the horizontal distance (HD) and vertical distance (VD) between buildings and channels. A case study in Puge County, Sichuan Province, demonstrated the high identification potential of the method for buildings susceptible to debris flows in large areas with only scarce information available. Meanwhile, We chose </strong><strong>a high-risk village</strong><strong> in Puge County to study </strong><strong>debris flow risk to buildings and residents. Different</strong><strong> types of days and diurnal periods were considered in </strong><strong>the analysis of societal risk to residents</strong><strong>. The </strong><strong>results</strong><strong> indicated that societal risk to residents on holidays is always higher than that on weekdays, and societal risk at night is also much higher than that in the daytime. </strong><strong>The identification results of buildings vulnerability provide valuable information regarding high-risk residential areas to governments and facilitate targeted measure design at the initial planning stage, and the proposed method of societal risk provides a basis for decision-making in the planning of mitigation countermeasures in a specific settlement.</strong></p>

scholarly journals Debris flows in the Eastern Italian Alps: seasonality and atmospheric circulation patterns

2014 ◽  
Vol 2 (12) ◽  
pp. 7197-7224 ◽  
Author(s):  
E. I. Nikolopoulos ◽  
M. Borga ◽  
F. Marra ◽  
S. Crema ◽  
L. Marchi
Keyword(s):  
Debris Flow ◽  
Atmospheric Circulation ◽  
Debris Flows ◽  
Large Scale ◽  
Rain Gauge ◽  
Italian Alps ◽  
Synoptic Pattern ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Synoptic Forcing

Abstract. The work examines the seasonality and large-scale atmospheric circulation patterns of debris flows in the Trentino-Alto Adige region (Eastern Italian Alps). Analysis is based on classification algorithms applied on a uniquely dense archive of debris flows and hourly rain gauge precipitation series covering the period 2000–2009. Results highlight the seasonal and synoptic forcing patterns linked to debris flows in the study area. Summer and fall season account for 92% of the debris flows in the record, while atmospheric circulation characterized by Zonal West, Mixed and Meridional South, Southeast patterns account for 80%. Both seasonal and circulation patterns exhibit geographical preference. In the case of seasonality, there is a strong north–south separation of summer–fall dominance while spatial distribution of dominant circulation patterns exhibits clustering, with both Zonal West and Mixed prevailing in the northwest and central east part of the region, while the southern part relates to Meridional South, Southeast pattern. Seasonal and synoptic pattern dependence is pronounced also on the debris flow triggering rainfall properties. Examination of rainfall intensity–duration thresholds derived for different data classes (according to season and synoptic pattern) revealed a distinct variability in estimated thresholds. These findings imply a certain control on debris-flow events and can therefore be used to improve existing alert systems.

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