Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast...Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.展开更多
Just as the cliff serves as a demarcation between two different worlds, there seems to the protagonist in The Catcher in the Rye the dichotomies between innocence and corruption, children and adults. While these duali...Just as the cliff serves as a demarcation between two different worlds, there seems to the protagonist in The Catcher in the Rye the dichotomies between innocence and corruption, children and adults. While these dualisms are projected in the story, they are also deconstructed and the characterization of Holden clearly shows the instability of those dualisms.展开更多
A model for calculating the erosion distance of soft sea cliff under wave loading is established based on the erosion mechanism of soft sea cliff under wave loading and for considering wave hydrodynamic and sea cliff ...A model for calculating the erosion distance of soft sea cliff under wave loading is established based on the erosion mechanism of soft sea cliff under wave loading and for considering wave hydrodynamic and sea cliff material parameters.The model is verified,and the parameters are regressed using an indoor flume experiment.The erosion distances of the sea cliff in the northeast of the Pingtan Island are calculated by the model,and the results are compared with the measured data.The maximum erosion occurs in static water level,the location of the maximum erosion moves up as the wave continues,and the erosion stops when the wave lasts for a period of time.The erosion does not occur until the wave height exceeds a critical value; however,the contribution of large waves to the erosion is not relatively substantial.The calculated erosion distances at two places in the northeast of Pingtan Island are 0.32 m and 0.26 m.展开更多
A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination o...A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination of several factors.The fall model in the present study accounts both spring seepage and wave action,resulting in undercutting and this fall affects only the topmost laterite and the just below sandstone in the cliff.Slippage in this area affects all the litho-units and hence the geologic characteristics of all the litho-units are considered for developing the slippage model.This mathematically derived model can be used in other cliffs exhibiting the same morphology as well as the one controlled by the same influencing factors.This model differs from other models in incorporating multi-lithounits as well as multi-notches.Varkala cliffs form a part of the aspiring geopark in the Global Geopark Network and hence a study on the cliff recession is a pressing requirement.展开更多
To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition a...To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition and structural analyses were carried out by means of X-ray diffraction(XRD), field emission scanning electron microscope(FESEM), transmission electron microscope(TEM), electron microprobe analysis(EMPA) and X-ray fluorescence spectra(XRF). Quartz, feldspar, mica, chlorite and aerinite as well as a small amount of amphibole, calcite, clinopyroxene, rutile, perovskite and apatite are recorded in the sediments. It is reported for the first time that the aerinite occurs in a high latitude area and in sediments paragenetic with mica and chlorite. The large span in grain size shows a typical characteristic of fluvioglacial sediments. Geochemistry characteristics(CIA, CIW, PIA, WIP and ICV) verify that there is virtually no chemical weathering. Mineralogy and geochemistry features of the UBC Cliffs sediments indicate that aerinite is accommodate to the high latitude and cold, dry climate. As the sediments show high similarity to those of their provenance, they have great significance in the identification of the forming condition and origin of the aerinite.展开更多
The aim of this work is to map the susceptibility of sites to landslides. To assess the susceptibility of the zone, GIS techniques were used. Susceptibility factors are selected and split into two groups: active and p...The aim of this work is to map the susceptibility of sites to landslides. To assess the susceptibility of the zone, GIS techniques were used. Susceptibility factors are selected and split into two groups: active and passive factors. Passive factors regroup all the intrinsic conditions existing on the field at all times. The active factors or triggering factors are present sporadically and are added to the passive factors to trigger a landslide. With the weighted overlay method using ArcGIS?, four scenarios have been developed. A first scenario where only passive factors are combined and three scenarios for which we have for each scenario the passive factors combined with an active factor. With these different scenarios, five levels of susceptibility are obtained in the zone. These levels range from very low to very high susceptibility. For the different scenarios, the results show that the zone consists mainly of very low to low susceptibility with at least 61% of the area, followed by moderate susceptibility (23.54% to 38.24%) and last land with high susceptibility to very high with less than 1% of the surface. Fields with high to very high susceptibility are located on the slopes of the hills. Among the active factors, only the rainfall significantly modifies the percentage of land susceptible to landslide but remains in the field of moderate susceptibility. The predicted susceptibilities are closer to the observed landslides around the Thies Cliff than to the Dias Horst.展开更多
Based on site studies, historical literature investigation and academic communication, this work aims to dig out the cultural significance in architectural and religious aspects conveyed in cliff carvings in the Bashu...Based on site studies, historical literature investigation and academic communication, this work aims to dig out the cultural significance in architectural and religious aspects conveyed in cliff carvings in the Bashu region. After casting a glance at the origin and evolution of Bashu culture and religion mainly involving Daoism and Buddhism recorded in forms of cliff carvings, we concentrated on discovering the national, regional and folk architectural characters implicated in cliff carvings at different sites within the Bashu region. The cliff carvings in this region vividly depicted the evolution of the architectural culture hereof. The essence of their religious and architectural connotations can be good stuff to be input in today’s architectural design philosophy.展开更多
A decrease in the amount of precipitation is observed on average 18 - 20 mm compared with the periods before the Aral crisis and the average annual temperature rise over the long-term period is 2.0°C in the Centr...A decrease in the amount of precipitation is observed on average 18 - 20 mm compared with the periods before the Aral crisis and the average annual temperature rise over the long-term period is 2.0°C in the Central part of Ustyurt. An increase in the Si index meaning an increase in the degree of drought every ten-flight is clearly expressed in the months March-July. Data Analysis 1981-2017 shows that within 36 years the species diversity in the monitoring sites of Kabanbay decreased by 2 - 3 times. In 1981 the number of species fluctuated between the values of 9 - 50, and in 2017 this figure is 4 - 17. The results of the analysis show that the forecast indicators of the old-current state (1981) of the vegetation coverage and number of species were stable or had tendencies with a low regressive character (r2 = 0.01). However, the current-state (2017) of the vegetation coverage and the species composition of the monitoring plots showed a low progressive trend (r2 = 0.03), i.e. in the future, the formation of plant communities with low vegetation coverage and species composition has a dominant status. The results show that in 1981, 65% - 80% of the species composition of plant communities consisted of halophyte and xerophyte groups. In 2017, this figure reaches 80% - 100%, i.e. this claims to increase xerophytization and halophytization of territories. An interesting fact is established with mesophyte group. In general, theoretically, the decrease in the number of mesophyte group of plants for 1981-2017 would have a direct correlation with the vegetation coverage and their active share in it. However, for 36 years, their active share in the vegetation coverage remained unchanged—amounting to 0% - 20%. Of course, in these years, the decrease in the number of mesophyte plants led to an increase in the number of plant communities, in which the proportion of vegetation coverage of mesophyte group is insignificant—0% - 5%. Despite the drought, the active part of the vegetation cover of mesophytic invasive species, such as Poa bulbosa, is consistently maintained.展开更多
This work presents the behavior of Segou sandstones in the laboratory and in the field conditions. Four types of sandstone are collected in the northern part of the Madina Kouta basin (eastern Senegal). These types of...This work presents the behavior of Segou sandstones in the laboratory and in the field conditions. Four types of sandstone are collected in the northern part of the Madina Kouta basin (eastern Senegal). These types of specimens are the white sandstones, the red sandstones, the purple sandstones and the sandstones with intercalation of pelites. Uniaxial tests are carried out on these specimens of sandstones. The Young Moduli (E) and the Uniaxial Compression Strengths (Rc) are higher for the white sandstone. Values of the mechanical parameters decrease slightly for red sandstones due to an increase of the amount of pelites in the composition of the rock. Decrease of mechanical parameters is more important for the purple facies due to an important network of fractures. The facies with weaker characteristics corresponds to the sandstones with intercalation of pelites. This is due to the soft nature of the pelites. The slope stability of the Cliff sides depends also on to these characteristics.展开更多
White puffy clouds drift past a bungalow facing a deep valley and a towering peak beyond it.Chirps of birds animate the idyllic scene without shattering its serenity.The bungalow with a wood-plank roof and mud walls i...White puffy clouds drift past a bungalow facing a deep valley and a towering peak beyond it.Chirps of birds animate the idyllic scene without shattering its serenity.The bungalow with a wood-plank roof and mud walls is featured in a video clip that Mouse Labo posted online on April 13.展开更多
基金the support provided by the Laboratory of Applied Research in Engineering Geology, Geotechnics, Water Sciences, and Environment, Setif 1 University, Algeria
文摘Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.
文摘Just as the cliff serves as a demarcation between two different worlds, there seems to the protagonist in The Catcher in the Rye the dichotomies between innocence and corruption, children and adults. While these dualisms are projected in the story, they are also deconstructed and the characterization of Holden clearly shows the instability of those dualisms.
基金The National Natural Science Foundation of China under contract No.41306051the Natural Science Foundation of Fujian Province of China under contract No.2015J01625
文摘A model for calculating the erosion distance of soft sea cliff under wave loading is established based on the erosion mechanism of soft sea cliff under wave loading and for considering wave hydrodynamic and sea cliff material parameters.The model is verified,and the parameters are regressed using an indoor flume experiment.The erosion distances of the sea cliff in the northeast of the Pingtan Island are calculated by the model,and the results are compared with the measured data.The maximum erosion occurs in static water level,the location of the maximum erosion moves up as the wave continues,and the erosion stops when the wave lasts for a period of time.The erosion does not occur until the wave height exceeds a critical value; however,the contribution of large waves to the erosion is not relatively substantial.The calculated erosion distances at two places in the northeast of Pingtan Island are 0.32 m and 0.26 m.
文摘A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination of several factors.The fall model in the present study accounts both spring seepage and wave action,resulting in undercutting and this fall affects only the topmost laterite and the just below sandstone in the cliff.Slippage in this area affects all the litho-units and hence the geologic characteristics of all the litho-units are considered for developing the slippage model.This mathematically derived model can be used in other cliffs exhibiting the same morphology as well as the one controlled by the same influencing factors.This model differs from other models in incorporating multi-lithounits as well as multi-notches.Varkala cliffs form a part of the aspiring geopark in the Global Geopark Network and hence a study on the cliff recession is a pressing requirement.
基金supported by the National Natural Sciences Foundation of China[Grant No:41872048,41372061,40972038]financial support from China Scholarship Council(No 201806010080).
文摘To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition and structural analyses were carried out by means of X-ray diffraction(XRD), field emission scanning electron microscope(FESEM), transmission electron microscope(TEM), electron microprobe analysis(EMPA) and X-ray fluorescence spectra(XRF). Quartz, feldspar, mica, chlorite and aerinite as well as a small amount of amphibole, calcite, clinopyroxene, rutile, perovskite and apatite are recorded in the sediments. It is reported for the first time that the aerinite occurs in a high latitude area and in sediments paragenetic with mica and chlorite. The large span in grain size shows a typical characteristic of fluvioglacial sediments. Geochemistry characteristics(CIA, CIW, PIA, WIP and ICV) verify that there is virtually no chemical weathering. Mineralogy and geochemistry features of the UBC Cliffs sediments indicate that aerinite is accommodate to the high latitude and cold, dry climate. As the sediments show high similarity to those of their provenance, they have great significance in the identification of the forming condition and origin of the aerinite.
文摘The aim of this work is to map the susceptibility of sites to landslides. To assess the susceptibility of the zone, GIS techniques were used. Susceptibility factors are selected and split into two groups: active and passive factors. Passive factors regroup all the intrinsic conditions existing on the field at all times. The active factors or triggering factors are present sporadically and are added to the passive factors to trigger a landslide. With the weighted overlay method using ArcGIS?, four scenarios have been developed. A first scenario where only passive factors are combined and three scenarios for which we have for each scenario the passive factors combined with an active factor. With these different scenarios, five levels of susceptibility are obtained in the zone. These levels range from very low to very high susceptibility. For the different scenarios, the results show that the zone consists mainly of very low to low susceptibility with at least 61% of the area, followed by moderate susceptibility (23.54% to 38.24%) and last land with high susceptibility to very high with less than 1% of the surface. Fields with high to very high susceptibility are located on the slopes of the hills. Among the active factors, only the rainfall significantly modifies the percentage of land susceptible to landslide but remains in the field of moderate susceptibility. The predicted susceptibilities are closer to the observed landslides around the Thies Cliff than to the Dias Horst.
基金Funded by China Postdoctoral Science Foundation (No. 2005037548).
文摘Based on site studies, historical literature investigation and academic communication, this work aims to dig out the cultural significance in architectural and religious aspects conveyed in cliff carvings in the Bashu region. After casting a glance at the origin and evolution of Bashu culture and religion mainly involving Daoism and Buddhism recorded in forms of cliff carvings, we concentrated on discovering the national, regional and folk architectural characters implicated in cliff carvings at different sites within the Bashu region. The cliff carvings in this region vividly depicted the evolution of the architectural culture hereof. The essence of their religious and architectural connotations can be good stuff to be input in today’s architectural design philosophy.
文摘A decrease in the amount of precipitation is observed on average 18 - 20 mm compared with the periods before the Aral crisis and the average annual temperature rise over the long-term period is 2.0°C in the Central part of Ustyurt. An increase in the Si index meaning an increase in the degree of drought every ten-flight is clearly expressed in the months March-July. Data Analysis 1981-2017 shows that within 36 years the species diversity in the monitoring sites of Kabanbay decreased by 2 - 3 times. In 1981 the number of species fluctuated between the values of 9 - 50, and in 2017 this figure is 4 - 17. The results of the analysis show that the forecast indicators of the old-current state (1981) of the vegetation coverage and number of species were stable or had tendencies with a low regressive character (r2 = 0.01). However, the current-state (2017) of the vegetation coverage and the species composition of the monitoring plots showed a low progressive trend (r2 = 0.03), i.e. in the future, the formation of plant communities with low vegetation coverage and species composition has a dominant status. The results show that in 1981, 65% - 80% of the species composition of plant communities consisted of halophyte and xerophyte groups. In 2017, this figure reaches 80% - 100%, i.e. this claims to increase xerophytization and halophytization of territories. An interesting fact is established with mesophyte group. In general, theoretically, the decrease in the number of mesophyte group of plants for 1981-2017 would have a direct correlation with the vegetation coverage and their active share in it. However, for 36 years, their active share in the vegetation coverage remained unchanged—amounting to 0% - 20%. Of course, in these years, the decrease in the number of mesophyte plants led to an increase in the number of plant communities, in which the proportion of vegetation coverage of mesophyte group is insignificant—0% - 5%. Despite the drought, the active part of the vegetation cover of mesophytic invasive species, such as Poa bulbosa, is consistently maintained.
文摘This work presents the behavior of Segou sandstones in the laboratory and in the field conditions. Four types of sandstone are collected in the northern part of the Madina Kouta basin (eastern Senegal). These types of specimens are the white sandstones, the red sandstones, the purple sandstones and the sandstones with intercalation of pelites. Uniaxial tests are carried out on these specimens of sandstones. The Young Moduli (E) and the Uniaxial Compression Strengths (Rc) are higher for the white sandstone. Values of the mechanical parameters decrease slightly for red sandstones due to an increase of the amount of pelites in the composition of the rock. Decrease of mechanical parameters is more important for the purple facies due to an important network of fractures. The facies with weaker characteristics corresponds to the sandstones with intercalation of pelites. This is due to the soft nature of the pelites. The slope stability of the Cliff sides depends also on to these characteristics.
文摘White puffy clouds drift past a bungalow facing a deep valley and a towering peak beyond it.Chirps of birds animate the idyllic scene without shattering its serenity.The bungalow with a wood-plank roof and mud walls is featured in a video clip that Mouse Labo posted online on April 13.
