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A Modified Certainty Coefficient Method(M-CF) for Debris Flow Susceptibility Assessment:A Case Study for the Wenchuan earthquake Meizoseismal Areas

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Journal of Mountain Science 2014年第5期11卷 1286-1297页

作者： WANG Jun YU Yan YANG Shun LU Gui-hong OU Guo-qiang Key laboratory of Mountain hazards and earth surface process Chinese Academy of Sciences Institute of Mountain hazards and environment Chinese Academy of Sciences University of Chinese Academy of Sciences

In the meizoseismal areas hit by the China Wenchuan earthquake on May 12, 2008, the disasterprone environment has changed dramatically, making the susceptibility assessment of debris flow more complex and uncertain. After the earthquake, debris flow hazards occurred frequently and effective susceptibility assessment of debris flow has become extremely important. Shenxi gully in Du Jiangyan city, located in the meizoseismal areas, was selected as the study area. Based on the research of disaster-prone environment and the main factors controlling debris flow, the susceptibility zonations of debris flow were mapped using factor weight method(FW), certainty coefficient method(CF) and geomorphic information entropy method(GI). Through comparative analysis, the study showed that these three methods underestimated susceptible degree of debris flow when used in the meizoseismal areas of Wenchuan earthquake. In order to solve this problem, this paper developed a modified certainty coefficient method(M-CF) to reflect the impact of rich loose materials on the susceptible degree of debris flow. In the modified method, the distribution and area of loose materials were obtained by field investigations and postearthquake remote sensing image, and four data sets, namely, lithology, elevation, slop and aspect, wereused to calculate the CF values. The result of M-CF method is in agreement with field investigations and the accuracy of the method is satisfied. The method has a wide application to the susceptibility assessment of debris flow in the earthquake stricken areas.

关键词： Wenchuan earthquake Disaster-prone environment Debris flow Susceptibility assessment Modified certainty coefficient method(M-CF)

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Debris Flow Formation process and Critical Hydrodynamic Conditions in the Meizoseismal Area of the Wenchuan earthquake

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Journal of Mountain Science 2015年第3期12卷 699-710页

作者： WANG Jun YU Yan PAN Hua-li QIAO Cheng OU Guo-qiang Key laboratory of Mountain Hazards and earth surface process Chinese Academy of Sciences Institute of Mountain Hazards and environment Chinese Academy of Sciences University of Chinese Academy of Sciences

Abstract： The Wenchuan earthquake generated strong surface disturbances and triggered a large number of loose deposits, resulting in the disaster- prone environment with special watershed hydrological characteristics. This paper was to propose a debris flow formation process and explore the permeability characteristics and critical hydrodynamic conditions of the loose deposits triggered by the earthquake. The Guo Juanyan gully （31005＇27＂ N to 31005＇46＂ N, 103036＇58＂ E to 103037＇09＂ E） in Du Jiangyan City, located in the meizoseismal areas of the Wenchuan earthquake, was chosen as the study area and the disaster-prone environment was analyzed. The formation process of the debris flow was first proposed using a stability analysis, and then, the permeability characteristics of loose deposits were determined via in situ permeability experiments. Finally, the critical 1 h rainfall was simulated through a distributed hydrological model and verified by field observations. The formation process of debris flow could be divided into three stages based on the relationship between the hydrodynamic force and loose deposit resistance. The critical 1 h rainfall amounts under three antecedent moisture conditions （I-dry, Ⅱ-normal and Ⅲ-wet） were 52 mm/h, 43 mm/h and 34 mm/h, respectively. This study proposed a debris flow formation process in the meizoseismal areas of the Wenchuan earthquake based on the stability analysis and defined the rainfall threshold for debris flow early warning at the local level, which is significant for debris flow mitigation and risk management.

关键词： Wenchuan earthquake Debris flow Disaster-prone environment Permeabilitycharacteristics Hydrodynamic condition

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Reservoir-landslide Hazard Assessment Based on GIS: A Case Study in Wanzhou Section of the Three Gorges Reservoir

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Journal of Mountain Science 2013年第6期10卷 1085-1096页

作者： WANG Meng QIAO Jian-ping Key laboratory of Geo-surface process and Mountain Hazards Institute of Mountain Hazards and Environment Chinese Academy of Science

Reservoir-landslide is mainly caused by changes in hydrodynamic conditions of slope interior at the time of water storage or discharge. The current study mainly focuses on the typical reservoirlandslide, but the sudden occurrence of some unknown landslides brought a lot of difficulties for hazards prevention. Therefore, we proposed a method to evaluate the regional scale reservoir-landslide hazard. We took Wanzhou section of Three Gorges Reservoir(China) as the study area and systemically and synthetically carried out the reservoir-landslide hazard evaluation under the condition of water level regulation. Firstly, we made reservoir-landslide susceptibility assessment by using the methods of spatial analysis and statistics based on geological and geomorphological materials and field survey data, and then, analyzed the regional-scale slope stability based on the infinite slope model used to analyze the bank slope stability change under the condition of water fluctuation, finally, developed a reservoir-landslide hazard evaluation model based on the results of susceptibility and stability. The hazard evaluation model was used to predict and evaluate the hazard change under the role of water level regulation. The results showed that the landslide hazard of the whole region decreased during water storage, landslide hazards increased during water discharge. The faster the regulation speed, the greater the slope hazard. The results can provide the basis for hazard management and regional land-use planning.

关键词： Reservoir-landslide Hazards assessment

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Competitive Contribution of Catalyst and Adsorption Roles of TiO_2 on the Degradation of AO7 Dye During Plasma Treatment

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Plasma Science and Technology 2013年第9期15卷 915-922页

作者： Nabila HADDOU Moufok Redounae GHEZZAR Fatiha ABDELMALEK Stephanie OGNIER Ahmed ADDOU laboratory of Science and Technical environment and Valorization University of Mostaganem laboratory of process Engineering and surface Treatment National School of ChemistryUniversity of Pierre and Marie Curie

In order to investigate the role of TiO2 during plasma treatment, the degradation of the dye AO7 has been studied by gliding arc discharge in the presence of a TiO2 catalyst （CGAD）. The results revealed that the adsorption of the dye on TiO2 is a physical adsorption in accordance with Langmuir isotherm, with a constant of adsorption KL ： 0.52 mg/L and a maximum adsorption capacity b = 18.1 mg/g. The temperature variation of the reaction medium made it possible to consider thermodynamic parameters. Indeed, the adsorption is exothermic （enthalpy： △H 〈 0）, and spontaneous （free enthalpy： △G 〈 0）. The negative entropy （△S 〈 0） confirms the affinity of the dye molecules for TiO2. 20 min of CGAD treatment in the pres- ence of an optimal quantity of TiO2 （2 g/L enabled us to bleach the solution of AO7 （100 μM） completely. The discoloration rate with and without the addition of TiO2 was 100% and 28%, respectively. 40 additional minutes of treatment allowed a total abatement of the chemical oxy- gen demand. The elimination of AO7 molecules during the plasma-catalytic treatment follows Langmuir-Hinshelwood （L-H） model kinetics. According to this model, the speed constant is kr = 14.97 mg-L-1 ·min-1 and the adsorption coefficient is KL-H= 0.010 L/mg. The latter being negligible compared to kr, adsorption is therefore weakly performed during the plasma treatment.

关键词： adsorption catalysis AO7 gliding arc discharge TiO_2 degradation

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Assessment of the Performance of WEPP in Purple Soil Area with Simulated Rainfall Experiments

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Journal of Mountain Science 2012年第4期9卷 570-579页

作者： FU Bin WANG Yukuan XU Pei YAN Kun Key laboratory of Mountain Hazards and earth surface process ChineseAcademy of SciencesChengdu 610041China Institute of Mountain Hazards and environment Chinese Academy of SciencesChengdu 610041China

The water erosion prediction project （WEPP） model is a popular water erosion prediction tool developed on the basis of the physical processes of water erosion. Although WEPP has been widely used around the world, its application in China is still insufficient. In this study, the performance of WEPP used to estimate the runoff and soil loss on purple soil （Calcaric Regosols in FAO taxonomy） sloping cropland was assessed with the data from runoff plots under simulated rainfall conditions. Based on measured soil properties, runoff and erosion parameters, namely effective hydraulic conductivity, inter-rill erodibility, rill erodibility, and critical shear stress were determined to be 2.68 mm h-1, 5.54 x l0^6 kg s-1 m-4, 0.027 s m-1 and 3-5 Pa, respectively, by using the recommended equations in the WEPP user manual. The simulated results were not good due to the low Nash efficiency of 0.41 for runoff and negative Nash efficiency for soil loss. After the four parameters were calibrated, WEPP performed better for soil loss prediction with a Nash efficiency of 0.76. The different results indicated that the equations recommended by WEPP to calculate parameters such as erodiblity and critical shear stress are not suitable for the purple soil areas, Sichuan Province, China. Although the predicted results can be accepted by optimizing the runoff and erosion parameters, more research related to the determination of erodibility and critical sheer stress must be conducted to improve the application of WEPP in the purple soil areas.

关键词： WEPP Soil erosion Simulated rainfall Purple soil Erodibility

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Tectonic modes of mantle convection and their implications for earth's tectonic evolution based on three-dimensional numerical simulations

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Science China earth Sciences 2025年第1期68卷 270-296页

作者： Song XIANG Jinshui HUANG Bingcheng WU School of earth and Space Sciences University of Science and Technology of China CAS Center of Excellence in Comparative Planetary Studies

Five tectonic modes of mantle convection are obtained and analyzed with three-dimensional numerical models in a spherical shell domain. The five tectonic convective modes are non-plate mobile-lid, plate-like mobile-lid, episodic plate-like mobile-lid, episodic stagnant-lid, and stagnant-lid convective modes, respectively. The typical characteristics of these five tectonic modes and their numerical classification criteria based on plateness, mobility, and their standard deviations are presented and discussed. The results show that the yield stress of the lithosphere has profound effects on the tectonic convective *** the gradual increase of yield stress, the tectonic mode of mantle convection changes from one to another sequentially through the aforementioned five modes. Additionally, as the Rayleigh number increases, the range of yield stress for the platelike mobile-lid convective mode decreases, and the dimensionless transition stress between different tectonic modes ***, the dimensional transition stress between the non-plate mobile-lid convective mode and plate-like mobile-lid convective mode increases with the increase of Rayleigh number, but decreases between other tectonic modes. Furthermore, we find that the transition stress between different tectonic modes is inversely proportional to the internal heating rate, with the transition stress decreasing as the internal heating rate increases. The fitting analysis of the transition stress between tectonic modes shows that earth's current plate tectonics correspond to a lithospheric yield stress of 150–250 MPa, which aligns with the strength of serpentinized mantle rock determined by experimental petrography. If the Archean mantle was 300°C warmer than it is today, then the earth was in an episodic stagnant-lid convective mode. The tectonic evolution of the earth's surface is closely related to the lithospheric strength and the process of thermal evolution. If the lithospheric strength w

关键词： Tectonic mode of mantle convection Plate-like mobile-lid convection Episodic plate-like mobile-lid convection Episodic stagnant-lid convection Plate tectonics and tectonic evolution of the earth

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Genesis of geothermal water in the hinterland of Guanzhong Basin， China: Insight from hydrochemical and isotopic analysis

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Journal of earth Science 2025年

作者： Jiangxia Wang Panpan Xu Hui Qian Yongqi Zang Qiming Wang Zhiyuan Ma School of Water and environment， Chang'an University Key laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education， Chang'an University Key laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources， Chang'an University

The Guanzhong Basin， located in Shaanxi Province， China， has abundant geothermal resources in its hinterland. Focusing on typical thermal reservoir structural units， namely the Xianli fault-step (XL) and Xi'an depression (XA)， this study reveals the genesis of geothermal water by combining hydrochemistry and environmental isotopes. The geothermal waters of XL uniformly correspond to the Na-Cl type with high contents of major ions， while the geothermal water of XA has complex hydrochemical types. The quartz geothermometer (with maximum steam loss) and Na-K-Ca geothermometer are recommended for XL and the quartz geothermometer (with no and maximum steam loss) and Na-K geothermometer for XA. Their temperature ranges are 99-159℃ and 93-146℃， respectively. The circulation depth of geofluids in XL and XA range from 2579 to 4766 m and from 2541 to 4330 m， with mean apparent ages of 21543 and 20345 yr B.P.， respectively. The geothermal water in XL originates from a mixture of sedimentary water and ancient infiltration water， and its formation mode was the vertical heat conduction with cooling process. In contrast， the geothermal water in XA originates from the dual process of cooling and mixing， with the process being dominated by ancient infiltration water and supplementation by modern infiltration water.

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Early millet use in West Liaohe area during early-middle Holocene

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Science China earth Sciences 2016年第8期59卷 1554-1561页

作者： MA ZhiKun YANG XiaoYan ZHANG Chi SUN YongGang JIA Xin School of Archaeology and Museology Peking University laboratory of Land surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences History and Culture Institute Chifeng University laboratory of earth surface process and environment School of Geographic and Oceanographic SciencesNanjing University

It is generally recognized that millet agriculture originated in northern China. However, the domestication process of foxtail millet(Setaria italica) and broomcorn millet(Panicum miliaceum) is still poorly understood. Based on statistical and morphological analyses of ancient millet starch grains, a tangible hypothesis has been proposed for the long-term domestication of green foxtail millet(S. viridis). However, the hypothesis requires validation by evidence from more regions and more archaeological finds. The West Liaohe region is one of the earliest regions of millet cultivation. Here, we report ancient starch grains recovered from 12 stone grinding tools from eight sites of the Xiaohexi culture(before 8.5 ka BP), Xinglongwa culture(8.2–7.4 ka BP), Zhaobaogou culture(7.0–6.4 ka BP), and Hongshan culture(6.5–5.0 ka BP) in the West Liaohe region of China. Our results indicate that the proportion of millet starch grains with wrinkled surfaces and rough edges, which are diagnostic of wild millet grasses, decreased from 13.0% to 3.4% from the Xiaohexi culture to the Hongshan culture. Millet starch grains measuring >16.8 ?m, a size class recorded only in domesticated foxtail millet, increased from 55.0% to 62.1%. These millet data imply that the process of millet domestication in the West Liaohe region began in the Xiaohexi period and continued up to the Hongshan period.

关键词： Plant domestication West Liaohe region Agricultural origin Neolithic Age Starch grain analysis

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Debris Flow Warning Threshold Based on Antecedent Rainfall:a Case Study in Jiangjia Ravine,Yunnan,China

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Journal of Mountain Science 2013年第2期10卷 305-314页

作者： GUO Xiao-jun CUI Peng LI Yong Key laboratory of Mountain Hazards and earth surface process and /Institute of Mountain Hazards and environment Chinese Academy of Sciences Asian Network on Debris Flow Graduate University of Chinese Academy of Sciences

Debris flows in Jiangjia Ravine in Yunnan province, China are not only triggered by intense storms but also by short-duration and low-intensity rainfalls. This reflects the significance of antecedent rainfall. This paper tries to find the debris flow- triggering threshold by considering antecedent rainfall through a case study in Jiangjia Ravine. From 23 debris flow events, the I-D （Intensity-Duration） threshold was found, which is very dose to the line of 95th percentile regression line of rainfall events, representing that 95% of rainfalls can potentially induce debris flows and reflects the limitation of I-D threshold application in this area. Taking into account the effect of antecedent rainfall, the debris flowtriggering threshold for rainfall quantity and intensity is statistically and empirically derived. The relationships can be used in debris flow warning system as key thresholds. Coupling with the rainfall characteristics in this area, new thresholds are proposed as triggering and warning thresholds.

关键词： I-D threshold debris flow warningsystem antecedent rainfall Jiangjia Ravine

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Simulation of two-phase debris flow scouring bridge pier

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Journal of Mountain Science 2017年第11期14卷 2168-2181页

作者： LIU Wei HE Si-ming Institute of Mountain Hazards and environment (IMHE) Chinese Academy of Sciences Key laboratory of Mountain Hazards and earth surface process Chinese Academy of Sciences Center for Excellence in Tibetan Plateau earth Sciences Chinese Academy of Sciences

Debris flows are typical two-phase flows, which commonly accompany erosion in mountainous areas, and may destroy bridge engineering by scouring. In this study, a physically-based two-phase model is applied for the simulation of debris flow scouring of bridge pier. In this model, the shear stress of debris flow on an erodible bed is considered to be a function of the solid shear stress, fluid shear stress, and volume fraction; accordingly, the erosion is incorporated into the two-phase model. Using a highaccuracy computational scheme based on the finite volume method, the model is employed for simulating a dynamic debris flow over an erodible bed. The numerical results are consistent with the experimental data, and verify the feasibility of the two-phase model. Moreover, a simple numerical test is performed to exhibit the fundamental behaviour of debris flow scouring of bridge pier, which shows that the degree of erosion on each side of the pier is higher compared to other areas. The scouring depth is influenced by the variations of solid volume fraction and velocity of debris flow and pier width.

关键词： Pier scouring Debris flow Two-phasemodel Numerical simulation

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