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By investigating the diffusion of information among social networks, and by presenting an analysis of apple growers in terms of the mechanism that underlies insurance decision-making, this paper fi...

We examined the impacts of venture capital investment (VCI) on the performance of online Peer-to-Peer (P2P) lending platforms. The research results show that: (1) Gaining the first round of VCI can...

To analyze the kinetic characteristics of a debris flow that occurred on 9 April 2000 in Tibet, China, a meshfree numerical method named smoothed particle hydrodynamics (SPH) is introduced, and two-dimensional and three-dimensional models are established in this work. Based on the numerical simulation, the motion process of this debris flow is reproduced, and the kinetic characteristics are analyzed combining with the field investigation data. In the kinetic analysis, the flow velocity, runout distance, deposition, and energy features are discussed. Simulation results show that the debris flow mass undergoes an acceleration stage after failure, then the kinetic energy gradually dissipates due to the friction and collision during debris flow propagation. Finally, the debris flow mass blocks the Yigong river and forms a huge dam and an extensive barrier lake. The peak velocity is calculated to be about 100 m/s, and the runout distance is approximately 8000 m. The simulation results basically match the data measured in field, thus verifying the good performance of the presented SPH model. This approach can predict hazardous areas and estimate the hazard intensity of catastrophic debris flow.

To analyse the kinetic characteristics of a rapid landslide that occurred on 9 April 2000 in Tibet, China, a meshfree numerical method named Smoothed Particle Hydrodynamics (SPH) is introduced, and two-dimensional and three-dimensional models are established in this work. Based on the numerical simulation, the landslide motion process is reproduced and the kinetic characteristics are analysed combined with the field investigation data. In the kinetic analysis, the landslide velocity, run-out distance, landslide accumulation, and energy features are discussed. Simulation results show that the landslide mass undergoes an acceleration stage after failure, then the kinetic energy dissipates gradually due to the friction and collision during the landslide propagation. Finally, the landslide mass blocks the Yigong river and forms a huge landslide dam and an extensive barrier lake. The peak velocity is calculated to be about 100 m/s, and the run-out distance is approximately 8,500 m. The simulation results basically match the data measured in field, thus verifying the good performance of the presented SPH model. This approach can provide a new way to predict hazardous areas and estimate the hazard intensity of rapid landslides.

Complex topographic features on the surfaces of rock avalanche deposits have been regarded as important indicators for understanding avalanche kinematics and dynamics. Based on a combination of remote sensing data and in-situ observations of surface landforms, including toreva blocks, transverse and longitudinal ridges, ridges separated by conjugate troughs, and hummocks, a giant Holocene rock avalanche on the Tibetan Plateau is recognized. This work aims to understand the kinematics of this event. In planview, the tongue-shaped rock avalanche exhibits a clear sequential distribution of various landforms. The translation zone (II) is characterised by toreva blocks originating from extension. In subzone III-1 of the accumulation zone (III), compression-related transverse ridges are well developed. Longitudinal ridges resulting from lateral velocity differences due to radial spreading are present in the front part of subzone III-1. Farther down, ridges separated by conjugate troughs (generated by a combination of compression and radial spreading) are common in subzone III-2. Subzone III-3 is characterised by abundant scattered hummocks with circular to oval shapes. Based on the distributions of these landforms, this rock avalanche is proposed to have mainly experienced a motion featuring laminar flow with radial spreading in its distal and marginal parts. During transport, three distinct processes appear to have occurred in the avalanche mass from the proximal to the distal zones: extension-dominated sliding in zone II, compression-dominated sliding in subzones III-1 and III-2, and rapid radial spreading in subzone III-3.

The Tibetan Plateau is a landslide-prone area in Southwest China. A large-scale ancient landslide named Luanshibao Landslide on the eastern margin of the Tibetan Plateau is described in this paper, based on field investigation and satellite image interpretation. The geological setting and morphometric properties of the landslide are presented. Especially, the hummocky landscape, a prominent feature in the deposit area, is described. The total run-out distance of this landslide is 3910 m and the maximum velocity is estimated to be 36.6 m/s. The angle of reach is analysed as the index expressing the mobility of the landslide. Its value is about 12 degrees, indicating the high landslide mobility. Field observation shows that this landslide was most likely triggered by an earthquake, and the seismic acceleration capable to induce this landslide is estimated to be 0.36 g. This landslide might have changed the course of the Litang River.

Identifying premonitory factors before final failure for long-existing landslide dams is of high importance in disaster prevention and risk reduction. In this study, a series of large-scale (outdoor) experiments were designed and conducted to identify premonitory factors that may be used in failure prediction for actual landslide dams. Surface deformation, especially dam-crest settlement, dam seepage-water turbidity and self-potential across the dam crest were selected as the target parameters. Changes in these parameters showed apparent correlations between each other. Based on the monitoring data obtained and the observation performed during the tests, the deformation and failure sequence of the dam model can be separated into four time-sequential periods: 1) Emergence of seepage water and front wetting. In this period, the monitoring parameters did not show any obvious changes. However, wetting was observed in the downstream face. 2) Hyperconcentrated flow discharge. In this period, water flowed out of the drainage channel, and the vertical deformation of the dam body became obvious, while the turbidity of the seepage water increased. 3) Emergence and development of cracks on the dam crest. In this period, the dam-crest settlement also increased. 4) Sudden collapse and final failure. In this period, self-potential across the dam crest decreased rapidly, and the dam-crest settlement reached a peak value. Therefore, dam-crest settlement, seepage-water turbidity and self-potential changes can be regarded as premonitory factors of landslide dam failure.

Attribute reduction is viewed as a kind of preprocessing steps for reducing large dimensionality in data mining of all complex systems. A great deal of researchers have proposed various approaches to reduce attributes or select key features in multicriteria decision making evaluation. In practice, the existing approaches for attribute reduction focused on improving the classification accuracy or saving the cost of computational time, without considering the influence of the reduction results on the original data set. To help address this gap, we develop an advanced novel attribute reduction approach combining Pearson correlation analysis with F test significance discrimination for the screening and identification of key characteristics related to the original data set. The proposed model has been verified using the financing ability evaluation data of 713 small enterprises of a city commercial bank in China. And the experimental results show that the proposed reduction model is efficient and effective. Moreover, our experimental findings help to locate the qualified partners and alleviate the difficulties faced by enterprises when applying loan.

High-intensity rainfall struck the Northern Kyushu area of Japan between 11 and 14 July 2012. This heavy rainfall triggered many shallow landslides, especially on the northeastern rim of Aso caldera, leading to significant loss of life and damage to many villages. One landslide site at Ichinomiya (Kumamoto Prefecture) was selected for detailed study. Field and laboratory investigations were conducted to identify the initiation mechanism of the shallow landslides during heavy rainfall. The thickness of the soil layer was determined using portable dynamic cone penetration tests. The soils became thinner (about 1 m) from the upper to the lower slope. In-situ infiltration tests indicate that hydraulic conductivity of this thin soil layer is low. During heavy rainfall events, most rainfall will transform into surface runoff instead of infiltration. The results of consolidated-undrained triaxial compression tests show that the effective friction angle and cohesion of the soil are 36.9° and 6.3 kPa, respectively. Soil behavior in response to increase in pore-water pressure was evaluated using a pore-water pressure controlled triaxial test. The results indicate that the steep slopes on the northeastern rim of Aso caldera will remain stable under normal rainfall conditions, due to the high shear strength of the soil. The probable initiation mechanism for the shallow landslides on the northeastern rim of Aso caldera suggests that the initial failure process begins with toe erosion caused by surface runoff during heavy rainfall. Due to the loss of the resistance force at the toe of slope, the slope will reach a critical condition when pore-water pressure in the slope also increases.

The Qianjiangping landslide is a large planar rock slide which occurred in July 14, 2003 shortly after the water level reached 135 m in the Three Gorges Reservoir, China. The landslide destroyed 4 factories and 129 houses, took 24 lives, and made 1,200 people homeless. Field investigation shows that the contributing factors for the landslide are the geological structure of the slope, the previous surface of rupture, the water level rise, and continuous rainfall. In order to reveal the mechanism and failure process of the landslide, numerical simulation was conducted on Qianjiangping slope before sliding. Based on the characteristics and the engineering conditions of the landslide, the topography and the geological profiles of Qianjiangping slope before sliding is reconstructed. The seepage field of Qianjiangping slope before sliding was simulated with the Geostudio software. The results show that ground water table rises and bends to the slope during the rise of water level, and the slope surface becomes partially saturated within the period of continuous rainfall. Using the ground water table obtained above, the failure process of Qianjiangping slope is simulated with the Flac3D software. The results demonstrate that the shear strain increment, displacement, and shear failure area of the slope increased greatly after the water level rose and continuous rained, and the landslide was triggered by the combined effect both of water level rise and continuous rainfall. The development of shear strain increment, displacement, and shear failure area of the slope shows that the landslide was retrogressive in the lower part of the slope and progressive in the upper part of the slope.

City green economy plays an important role in the development of low-carbon economy and the achievement of sustainable development of economy, society and ecological environment. From the perspective of economy, society, environment and resources, the evaluation of the green economy in urban areas tends to offer us a new insight into the green economy of cities. This paper is about the creation of a novel urban green economy evaluation model and its application. First of all, we established a city green economy evaluation index system based on R cluster analysis and coefficient of variation. Secondly, based on the nonlinear weighted utilizing entropy weight method, a city green economy evaluation model is established based on inferior constraints. Thirdly, by comparing the differences between evaluation rankings under inferior constraints and non-inferior constraints, the advantageous factors and the disadvantageous ones in urban green economy development are obtained. The proposed model has been verified with the data on 15 sub-provincial cities in China. Empirical analysis results show that: (1) The proposed approach can accurately find out the advantageous and disadvantageous factors for each sub-provincial city; (2) In the evaluation of green economy development, the order of importance of the three criterion layers is X1 Economy development > X2 Social livelihood of the people > X3 Resources and environment; (3) Local governments should implement differential, reasonable policies in order to improve their green economy development. Moreover, our research is not only significant for developing green economy in China’s sub-provincial cities, but also serves as a reference for the development of green economy in other cities in the world.

This paper presents preliminary results of geophysical investigations carried out on recent landslide dams in the Kii Peninsula, Japan with purpose of studying internal structures of the landslide dams in relation to groundwater flow which may cause potential failure by piping. Model tests were also conducted to confirm the method of monitoring groundwater flow through the dams and propose premonitory indices that can be used to predict major failure by piping. Results obtained from microtremor chain array survey (MCAS) shows that the internal characteristics of the landslide dams are related to the density and material compositions of the blockages. Also, results obtained from model tests confirmed that self-potential measurement is effective in monitoring groundwater flow while decrease in groundwater level and increase in turbidity can be used as premonitory indices for predicting landslide dam failure by piping.

Water level variation is one of the main triggering factors of landslides in reservoirs. In the Three Gorges Reservoir, China, the field monitoring data of the Shuping landslide shows that the sliding deformation accelerates during water level drawdown. In order to study the influence of water level drawdown on landslide movements in the reservoir, series of slope model tests were conducted to simulate the response of water level drawdown on the slope. The movement of slopes with different soil permeability is presented along with the generation and dissipation of pore water pressure in the slopes under water level variation. Experimental results show that the permeability of slope material controls the dissipation of pore water pressure in the slope under water level drawdown. However, if the permeability is high enough, the effect of the permeability change on the dissipation time of pore water pressure will not be obvious. During the mitigation and prevention of landslide with low permeability soil in reservoir, more attention should be focused on the drainage of ground water to quickly reduce the pore water pressure after water level drawdown in reservoir.

Landslide dams are formed when landslides move into mountain valleys, and potential flooding to the downstream area becomes secondary hazard of landslides. Sometimes, the potential flood threatens larger areas and more population than that by the landslide itself, so it is very important to find a quick method of evaluating the possibility of landslide dam failure. Generally, landslide dam failure can be caused by overtopping and piping. It is relatively easier to predict failure triggered by overflow because water level in the upstream area can be monitored. For those failure caused by piping, it is difficult to be predicted, because piping depends on the internal structure and composition of the landslide dam. If the internal structure of the landslide dam can be clarified, then it will become possible to evaluate the possibility of piping-induced landslide dam failure. In this paper, the possibility of using microtremor array survey to understand the internal structure of landslide dam and evaluate the potential of piping failure is examined.

The Qianjiangping landslide is a large translational rock slide which occurred in July 14, 2003 shortly after the water level reached 135 m in the Three Gorges Reservoir, China. The landslide destroyed 346 houses, took 24 lives and rendered 1,200 people homeless. In order to understand the failure process of the landslide, numerical simulation was conducted on Qianjiangping slope before sliding. Based on pre-failure characteristics and structural conditions of the landslide, topographic and geological profile of Qianjiangping slope was reconstructed. Seepage field of the Qianjiangping slope before sliding was simulated with the SEEP/W module of GeoStudio software. The results show that the groundwater table rose and infiltrated into the slope during the rise in water level, and the slope surface became partially saturated during the period of continuous rainfall. Using the groundwater table data, the failure process of the Qianjiangping slope was simulated with Flac3D software. The result shows that the shear strain increment, displacement and plastic state region of the slope increased greatly after water level rise and continuous rainfall. Consequently, the landslide was triggered by the combined effects of water level rise and rainfall. The simulated results of the shear strain increment, displacement and plastic state region of the slope show that the failure surface was located in the weak carbonaceous shale layer, and was retrogressive in the lower part of the slope and progressive in the upper part. Analysis of the simulation results before and after the water level rise and rainfall, it was observed that reservoir water level rise was the main triggering factor for the Qianjiangping landslide.

金沢大学理工研究域地球社会基盤学系, BackgroundTyphoon Wipha struck Izu Oshima Island on 16 October 2013, bringing heavy rainfall. It triggered widespread landslides on the western slopes of Izu Oshima Island, and caused significant loss of life and serious property damage. Authors have conducted both field investigations and laboratory experiments in an effort to understand the initiation mechanism of the shallow landslides triggered by heavy rainfall.ResultsPyroclastic-fall deposits on the slopes are well-graded fine sand with silt, and with high specific gravity and void ratio. These soil properties will affect the mechanical and hydraulic characteristics of soil. The results of consolidated-undrained triaxial tests show that the effective internal friction angle of soil is 38.7 degrees. The results of triaxial tests using pore-water pressure control show that static liquefaction can occur in porous pyroclastic-fall deposit layers due to rainfall infiltration.ConclusionsThe effective strength of pyroclastic-fall deposits on the upper slope is quite high. Even though the slope is very steep (over 30 degrees), it can remain stable while in an unsaturated condition. Due to heavy rainfall and the porosity of the pyroclastic-fall deposits, rainfall can quickly infiltrate into soil layer. Moreover, the interface above the underlying basalt will stop groundwater infiltration, acting as an impervious boundary. With increase of groundwater level, the effective strength of the porous soil will decrease. Finally, static liquefaction can be triggered, leading to the generation of shallow landslides on the upper slopes.

In the early morning of 20 August 2014, a high-intensity/low-duration rainstorm occurred in Hiroshima City, in southwest Japan. Within 3 h, the rainfall exceeded 200 mm, which is more than twice the monthly-average for this area. This heavy rainfall triggered 107 debris flows and 59 shallow slides, which caused 44 injuries, and 74 deaths. 133 houses were destroyed and an additional 296 houses were severely damaged. Most of the debris flows occurred in heavily weathered granite slopes, while others occurred in weathered hornfels slopes. A field investigation on two of the gullies in which the debris flows occurred was conducted in order to better understand the characteristics of the debris flows. The main purpose of this investigation was to understand the geomorphological and geological conditions, the soil properties, and the initiation/traveling mechanisms of the debris flows. The longitudinal and cross-sectional profiles along the two gullies were measured, beginning at the source areas and ending at the downstream limits of the deposition areas. For soil property determination, disturbed and undisturbed soil samples were collected for laboratory tests which included in-situ density measurement, grain size distribution analysis and triaxial compression tests. In the triaxial compression tests, consolidated-undrained compression tests under different confining stresses were conducted to measure the strength parameters of the strongly-weathered granite. Pore-water pressure controlled triaxial test was conducted to simulate the failure process of the slope given an increase of the pore-water pressure. Chemical analyses of the granite samples were also conducted in order to understand the degree of weathering of the granite in the debris flow gully. A high intensity, short duration, localized rainfall event initiated debris flows in very steep slopes. These were initiated as a thin sliding mass in weathered coarse-grained granite and hornfels, and became two different types of debris flow after traveling down the slopes. The slope angle and the cross section of the gully, and the grain size of the debris significantly controlled the motion behavior of the debris flows.