Cause Analysis of Zhaohe Debris Flow in Erlong Town in Zhenping County in Henan Province

2014 ◽  
Vol 638-640 ◽  
pp. 2071-2074
Author(s):  
Wei Zhang
Keyword(s):  
Debris Flow ◽  
Wide Distribution ◽  
Human Engineering ◽  
Mountain Areas ◽  
Flow Area ◽  
Cause Analysis ◽  
Climate Conditions ◽  
Neotectonic Movement ◽  
Engineering Activity ◽  
Steep Terrain

Debris flow is one of the major geological disasters in mountain areas. This paper systematically analyzes the influence of steep terrain conditions, the development of regional structure, neotectonic movement and earthquake, wide distribution of debris, human engineering activity and rainfall concentrated climate conditions in debris flow area. The dominant factors inducing Zhaohe debris flow were revealed, providing guidance for the debris flow disaster prevention, as well as reference for the same area debris flow cause analysis.

scholarly journals Analysis of the Topography Characteristics of a Debris-Flow Area Using Drones

2019 ◽  
Vol 19 (4) ◽  
pp. 127-133
Author(s):  
Namgyun Kim ◽  
Man-Il Kim ◽  
Jawhwan Kwak ◽  
ByongHee Jun
Keyword(s):  
Debris Flow ◽  
Flow Area

scholarly journals 2D Runout Modelling of Hillslope Debris Flows, Based on Well-Documented Events in Switzerland

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 70 ◽  
Author(s):  
Florian Zimmermann ◽  
Brian W. McArdell ◽  
Christian Rickli ◽  
Christian Scheidl
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Mass Movement ◽  
Clay Content ◽  
Systematic Evaluation ◽  
Mountain Areas ◽  
Flow Processes ◽  
Friction Parameters ◽  
Cohesive Interaction ◽  
Hillslope Debris Flow

In mountain areas, mass movements, such as hillslope debris flows, pose a serious threat to people and infrastructure, although size and runout distances are often smaller than those of debris avalanches or in-channel-based processes like debris floods or debris flows. Hillslope debris-flow events can be regarded as a unique process that generally can be observed at steep slopes. The delimitation of endangered areas and the implementation of protective measures are therefore an important instrument within the framework of a risk analysis, especially in the densely populated area of the alpine region. Here, two-dimensional runout prediction methods are helpful tools in estimating possible travel lengths and affected areas. However, not many studies focus on 2D runout estimations specifically for hillslope debris-flow processes. Based on data from 19 well-documented hillslope debris-flow events in Switzerland, we performed a systematic evaluation of runout simulations conducted with the software Rapid Mass Movement Simulation: Debris Flow (RAMMS DF)—a program originally developed for runout estimation of debris flows and snow avalanches. RAMMS offers the possibility to use a conventional Voellmy-type shear stress approach to describe the flow resistance as well as to consider cohesive interaction as it occurs in the core of dense flows with low shear rates, like we also expect for hillslope debris-flow processes. The results of our study show a correlation between the back-calculated dry Coulomb friction parameters and the percentage of clay content of the mobilised soils. Considering cohesive interaction, the performance of all simulations was improved in terms of reducing the overestimation of the observed deposition areas. However, the results also indicate that the parameter which accounts for cohesive interaction can neither be related to soil physical properties nor to different saturation conditions.

Research on Risk Level of Debris Flow in an Area

2014 ◽  
Vol 638-640 ◽  
pp. 2015-2018
Author(s):  
Qing Nian Yang ◽  
Shuai Tao Wu ◽  
Zhi Li
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Evaluation Method ◽  
Risk Level ◽  
The Tibetan Plateau ◽  
Adverse Conditions ◽  
Southeastern Margin ◽  
The Sichuan Basin ◽  
Original Vegetation ◽  
Steep Terrain

The research targets at the transition zone from the southeastern margin of the Tibetan Plateau to the Sichuan Basin; it is shown according to field survey: from 2008 to 2010, debris flow occurred twice, resulting in missing of two people, destruction on a lot of farmland and other serious disasters. Such the debris flows were because that the original vegetation was severely damaged after “5.12” earthquake, a lot of loose blocks were scattered in slopes and valleys, and also stimulated by abundant rainfall during rainy season, local steep terrain, as well as narrow valleys. The paper makes qualitative and quantitative evaluation on risk of debris flow within the region by single-valley debris flow risk evaluation method as proposed by Liu Xilin and Tang Chuan et al. it is shown from the results that the risk level H is 0.55, within scope of moderate risk. In case of any adverse conditions, debris flows may occur again.

scholarly journals Relationship between the accumulation of sediment storage and debris-flow characteristics in a debris-flow initiation zone, Ohya landslide body, Japan

2017 ◽  
Vol 17 (11) ◽  
pp. 1923-1938 ◽  
Author(s):  
Fumitoshi Imaizumi ◽  
Yuichi S. Hayakawa ◽  
Norifumi Hotta ◽  
Haruka Tsunetaka ◽  
Okihiro Ohsaka ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Laser Scanning ◽  
Flow Characteristics ◽  
Sediment Supply ◽  
Physical Analysis ◽  
Saturated Flow ◽  
Initiation Zone ◽  
Landslide Body ◽  
Steep Terrain

Abstract. Debris flows usually occur in steep mountain channels and can be extremely hazardous as a result of their destructive power, long travel distance, and high velocity. However, their characteristics in the initiation zones, which could possibly be affected by temporal changes in the accumulation conditions of the storage (i.e., channel gradient and volume of storage) associated with sediment supply from hillslopes and the evacuation of sediment by debris flows, are poorly understood. Thus, we studied the relationship between the flow characteristics and the accumulation conditions of the storage in an initiation zone of debris flow at the Ohya landslide body in Japan using a variety of methods, including a physical analysis, a periodical terrestrial laser scanning (TLS) survey, and field monitoring. Our study clarified that both partly and fully saturated debris flows are important hydrogeomorphic processes in the initiation zones of debris flow because of the steep terrain. The predominant type of flow varied temporally and was affected by the volume of storage and rainfall patterns. Fully saturated flow dominated when the total volume of storage was  <  10 000 m3, while partly saturated flow dominated when the total volume of the storage was  >  15 000 m3. Debris flows form channel topography which reflects the predominant flow types during debris-flow events. Partly saturated debris flow tended to form steeper channel sections (22.2–37.3°), while fully saturated debris flow tended to form gentler channel sections ( <  22.2°). Such relationship between the flow type and the channel gradient could be explained by a simple analysis of the static force at the bottom of the sediment mass.

scholarly journals Tracking the local seismicity level in the active influence zone of the southern Uzbekistan reservoirs

2021 ◽  
Vol 264 ◽  
pp. 02043
Author(s):  
Lutfulla Khamidov ◽  
Mahmud Turapov ◽  
Soqijon Mahkamov ◽  
Farkhod Artikov ◽  
Shavkat Suyunov
Keyword(s):  
Negative Impact ◽  
Tien Shan ◽  
Activity Levels ◽  
Human Engineering ◽  
Seismogenic Fault ◽  
Strong Earthquakes ◽  
Local Seismicity ◽  
Local Earthquakes ◽  
Engineering Activity ◽  
Mountain System

Assessment of local seismicity caused by human engineering activity is a necessity after several earthquakes have been recorded in world practice, which destroyed a hydraulic structure, a dam and accompanied by human casualties. The Tupalang, Gissarak and Pachkamar reservoirs, operated in southern Uzbekistan, are located in the mountain system of the southern part of the Tien Shan seismogenic fault. According to the general seismic zoning, the zones where these reservoirs are located are classified as 8-9 magnitude shakes during strong earthquakes. Localisation of local earthquakes associated with the operation of these reservoirs is necessary for taking operational measures to prevent possible emergencies associated with an increase in the level of technogenic seismicity. Methods for assessing the local seismic regime were used to track the level of local seismicity. The catalogs of local earthquakes occurring in the zone of active influence of reservoirs have been compiled. The seismic activity levels and changes in the angle of inclination of the recurrence of earthquakes were determined for each object separately. The dependence of the variation in the level of local seismicity on the mode of operation of reservoirs has been revealed. Several evidence of the negative impact of large hydraulic reservoirs on the deformation and seismic state of the zones of influence of reservoirs in southern Uzbekistan have been identified.

Risk Assessment of the Debris Flow Gully in Tibet Southeast

2015 ◽  
Vol 724 ◽  
pp. 347-352
Author(s):  
Jiang Xu ◽  
Qiang He ◽  
Pei Qing Wang ◽  
Lu Lu ◽  
Dong Dong Chen
Keyword(s):  
Risk Assessment ◽  
Debris Flow ◽  
Assessment Model ◽  
Risk Assessment Model ◽  
Disaster Prevention ◽  
Correlation Ratio ◽  
Human Engineering ◽  
The Core ◽  
Core Content ◽  
Debris Flow Disaster

Risk assessment of debris flow is the core content and decision-making basis for debris flow disaster forecasting and the disaster prevention work. It is a comprehensive analysis for the geological, climate, rainfall, historical disaster activities and human engineering activities in some certain areas which may be in danger conditions, so as to determine the occurrence probability of debris flow. In this study, risk assessment model of the debris flow gully in Tibet southeast area is established. According to the correlation ratio of risk assessment indexes and the debris flow occurrence, the assessment indexes can be divided into three levels and defined with some certain values according to the correlation of debris flow occurrence. Finally, the risk assessment of debris flow gully in Tibet southeast area is conducted, and model outputs achieve a good result.

scholarly journals Early warning of debris flow using optimized self-organizing feature mapping network

2020 ◽  
Vol 20 (7) ◽  
pp. 2455-2470
Author(s):  
Xuedong Wang ◽  
Cui Wang ◽  
Chaobiao Zhang
Keyword(s):  
Neural Network ◽  
Debris Flow ◽  
Early Warning ◽  
Rainfall Threshold ◽  
Liaoning Province ◽  
Feature Mapping ◽  
Threshold Method ◽  
Flow Area ◽  
Competitive Neural Network ◽  
Self Organizing

Abstract Early warning of debris flow is one of the core contents of disaster prevention and mitigation work for debris flow disasters. There are few early warning methods based on the combination of rainfall threshold and geological environment conditions. In this paper, we presented an early warning method for debris flow based on the infinite irrelevance method (IIM) and self-organizing feature mapping (SOFM), and applied it to Liaoning Province, China. The proposed model consisted of three stages. Firstly, eight geological environmental conditions and two rainfall-inducing conditions were selected by analyzing the factors affecting the development of debris flow in the study area, and the rainfall threshold for debris flow outbreak was 150 mm. Secondly, the correlation between various factors was analyzed by IIM, which prevented the blindness of parameter selection and improved the prediction accuracy of the model. Finally, SOFM was employed to predict the test data. Experimental results showed that the IIM-SOFM model had a strong early warning ability. When 25 samples of low-frequency debris flow area were selected, the accuracy rate of the IIM-SOFM model with optimized network structure parameters was 100%, which it was obviously superior to the rainfall threshold method, BP neural network and competitive neural network. Consequently, it is feasible to use the IIM-SOFM model for early warning of debris flow, outperforming traditional machine learning methods.

scholarly journals Transient thermal effects in Alpine permafrost

2009 ◽  
Vol 3 (1) ◽  
pp. 85-99 ◽  
Author(s):  
J. Noetzli ◽  
S. Gruber
Keyword(s):  
Climatic Conditions ◽  
Balance Model ◽  
High Mountain ◽  
Transient Effects ◽  
Mountain Areas ◽  
Past Climate ◽  
Climate Conditions ◽  
The Past ◽  
Numerical Experimentation ◽  
Time Periods

Abstract. In high mountain areas, permafrost is important because it influences the occurrence of natural hazards, because it has to be considered in construction practices, and because it is sensitive to climate change. The assessment of its distribution and evolution is challenging because of highly variable conditions at and below the surface, steep topography and varying climatic conditions. This paper presents a systematic investigation of effects of topography and climate variability that are important for subsurface temperatures in Alpine bedrock permafrost. We studied the effects of both, past and projected future ground surface temperature variations on the basis of numerical experimentation with simplified mountain topography in order to demonstrate the principal effects. The modeling approach applied combines a distributed surface energy balance model and a three-dimensional subsurface heat conduction scheme. Results show that the past climate variations that essentially influence present-day permafrost temperatures at depth of the idealized mountains are the last glacial period and the major fluctuations in the past millennium. Transient effects from projected future warming, however, are likely larger than those from past climate conditions because larger temperature changes at the surface occur in shorter time periods. We further demonstrate the accelerating influence of multi-lateral warming in steep and complex topography for a temperature signal entering the subsurface as compared to the situation in flat areas. The effects of varying and uncertain material properties (i.e., thermal properties, porosity, and freezing characteristics) on the subsurface temperature field were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over time periods of decades to centuries. At the end, the model was applied to the topographic setting of the Matterhorn (Switzerland). Results from idealized geometries are compared to this first example of real topography, and possibilities as well as limitations of the model application are discussed.

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