The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevita-bly affected by the orbiter attitude jitter.Therefore,it is necessary to conduct preliminary research on the stereo m...The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevita-bly affected by the orbiter attitude jitter.Therefore,it is necessary to conduct preliminary research on the stereo mapping camera equipped on lunar orbiter before launching.In this work,an imaging simulation method consid-ering the attitude jitter is presented.The impact analysis of different attitude jitter on terrain undulation is conduct-ed by simulating jitter at three attitude angles,respectively.The proposed simulation method is based on the rigor-ous sensor model,using the lunar digital elevation model(DEM)and orthoimage as reference data.The orbit and attitude of the lunar stereo mapping camera are simulated while considering the attitude jitter.Two-dimensional simulated stereo images are generated according to the position and attitude of the orbiter in a given orbit.Experi-mental analyses were conducted by the DEM with the simulated stereo image.The simulation imaging results demonstrate that the proposed method can ensure imaging efficiency without losing the accuracy of topographic mapping.The effect of attitude jitter on the stereo mapping accuracy of the simulated images was analyzed through a DEM comparison.展开更多
Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods ...Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods may generate analytical singularities for conditions of undulating terrain. Based on basic geomagnetic field theories, in this study an improved magnetic field expression is derived using an integration method of variable substitution, and all singularity problems for the entire space without a source are discussed and solved. This integration process is simpler than that of previous methods, and final integral results with a more uniform form. AT at all points in the source-flee space can be calculated without requiring coordinate transformation; thus forward modeling is also simplified. Corresponding model tests indicate that the new magnetic field expression is more correct because there is no analytical singularity and can be used with undulating terrain.展开更多
This paper describes a geographic information system(GIS)-based method for observing changes in topography caused by the initiation, transport, and deposition of debris flows using highresolution light detection and r...This paper describes a geographic information system(GIS)-based method for observing changes in topography caused by the initiation, transport, and deposition of debris flows using highresolution light detection and ranging(LiDAR) digital elevation models(DEMs) obtained before and after the debris flow events. The paper also describes a method for estimating the volume of debris flows using the differences between the LiDAR DEMs. The relative and absolute positioning accuracies of the LiDAR DEMs were evaluated using a real-time precise global navigation satellite system(GNSS) positioning method. In addition, longitudinal and cross-sectional profiles of the study area were constructed to determine the topographic changes caused by the debris flows. The volume of the debris flows was estimated based on the difference between the LiDAR DEMs. The accuracies of the relative and absolute positioning of the two LiDAR DEMs were determined to be ±10 cm and ±11 cm RMSE, respectively, which demonstrates the efficiency of the method for determining topographic changes at an scale equivalent to that of field investigations. Based on the topographic changes, the volume of the debris flows in the study area was estimated to be 3747 m3, which is comparable with the volume estimated based on the data from field investigations.展开更多
Static effort of rock mass very rarely causes of rock burst in polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or s...Static effort of rock mass very rarely causes of rock burst in polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or sliding in roof layers above the exploited panel in coal seam, sometime in a distance from actual exploitation. Sliding, as a rule occurs in fault zone and tremors in it are expected, but monolithic layer rupture is very hard to predict. In a past few years a practice of analyzing state of deformation in high energy seismic tremors zones has been employed. It let gathering experience thanks to witch determination of dangerous shape of reformatted roof is possible. In the paper some typical forms of roof rocks deformations leading to seismic tremor occurrence will be presented. In general these are various types of multidirectional rock layers bending. Real examples of seismic events and rock bursts will be shown.展开更多
In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential ro...In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.展开更多
Phosphorus fractions and adsorption-release characteristics of sediments in the Zhujiang （Pearl） River estuary wetland were investigated. Results showed that the total phosphorus （TP） content in surface sediments ...Phosphorus fractions and adsorption-release characteristics of sediments in the Zhujiang （Pearl） River estuary wetland were investigated. Results showed that the total phosphorus （TP） content in surface sediments ranged from 648.9 mg/kg to 1064.0 mg/kg; inorganic phosphorus （IP） was the major fraction of TP and ranged from 422.5 mg/kg to 643.9 mg/kg. Among the inorganic phosphorus, the main fractions were phosphorus bound to A1 and Fe （Fe/A1-P）, and calcium-bound phosphorus （Ca-P）, accounting for 23%-42% and 21%-67% of IP, respectively. The vertical distribution of TP contents were significantly positive correlated with organic phosphorus （Org-P） and Fe/A1-P contents. The bio-available phosphorus contents in vertical sediments varied from 128.6 mg/kg to 442.9 mg/kg, mainly existed in Fe-AI/P fraction, and increased from the bottom to top sediments. The transport of phosphorus in sediment-water in- terface was controlled by the soil characteristics. The active Fe and A1 content was considered as the main factor that determines adsorp- tion capacity in vegetated marsh wetland. The P buffering capacity of the sediments in vegetated marsh wetland was greater than that in mudflat wetland. The potential risk of eutrophication in the study area is high. Reducing terrestrial phosphorus discharge and preventing the sediment Fe/A1-P release to the interstitial water are the possible solutions to reduce the risk of eutrophication in estuary wetlands, and planting vegetation in estuary wetland can also reduce the release of phosphorus in surface sediment.展开更多
In order to investigate the surface deformation caused by coal mining and to reduce environmental damage, more accurate information of dynamic subsidence basins, caused by coal mining, is needed. Based on theological ...In order to investigate the surface deformation caused by coal mining and to reduce environmental damage, more accurate information of dynamic subsidence basins, caused by coal mining, is needed. Based on theological theory, we discuss surface deformation mechanism of dynamic subsidence on the assumption that both the roof and the coal seam are visco-elastic media, put forward the idea that the principle of surface deformation is similar to that of roofs, except for their parameters. Therefore, a surface deforma- tion equation can be obtained, given the equation of the roof deformation derived.from using a HIM rhe- ological model. In the end, we apply the equation of surface deformation as a practical subsidence prediction in a coal mine. Given the theologic properties of a rock mass, the results of our research of a dynamic subsidence basin can predict the development of surface deformation as a function of time, which is more important than the ultimate subsidence itself. The results indicate that using rheological theory to calculate the deformation of a dynamic subsidence basin is suitable and provides some reference for surface deformation of dynamic subsidence basins.展开更多
Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. ...Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. From the spectral analysis of the results, we can see that the periods of displacements are 12 months and the semi-periods are 6 months. The results also show that the maximum seasonal displacements can reach 20 mm and even larger. The covariance analyses and significance tests show that the coefficients of 96 percent of the stations are significant at the 0.1 significance level. The results show that one of the reasons of the vertical crustal displacements is the changing surface fluid loads.展开更多
In this paper, using focal mechanism solutions of moderate-strong earthquakes in Yunnan and its adjacent areas, and based on the statistical analysis of the parameters of focal mechanism solutions, we discussed in det...In this paper, using focal mechanism solutions of moderate-strong earthquakes in Yunnan and its adjacent areas, and based on the statistical analysis of the parameters of focal mechanism solutions, we discussed in detail the earthquake fault types and the characteristics of the modern tectonic stress field in the Yunnan region. The results show that most moderate-strong earthquakes occurring in the Yunnan region are of the strike-slip type, amounting to 80% of the total. Normal faulting and normal with strike-slip and reverse and reverse with strike-slip earthquakes is almost equivalent in proportion, about 8% each. The tectonic stress field of the Yunnan region is near-horizontal, and the dips of earthquake fault planes are large. There are three main dynamic sources acting on the Yunnan region: one is the NE, NNE and NNW-directed acting force from Myanmar, Laos and Vietnam; the second is the SE-SSE directed force from the Sichuan and Sichuan-Yunnan rhombus block and the third is the NW-NNW directed force from the South China block. These three acting forces have controlled the faulting behavior of the main faults and the characteristics of strong earthquake activity of Yunnan and its adjacent regions.展开更多
Each nationality has formed unique ethnic culture in the long history. Ethnic culture is spatially reflected byethnic distribution. The distribution of nationalities is influenced by ethnic history, culture, society a...Each nationality has formed unique ethnic culture in the long history. Ethnic culture is spatially reflected byethnic distribution. The distribution of nationalities is influenced by ethnic history, culture, society and religion, alsoaffected by regional physical setting. This paper analyzes the relationship between ethnic distribution pattern and naturalsetting with contrast analytical method. The digital elevation model (DEM) is established on basis of contour map on ascale of 1:250,000 in the Nujiang River basin, Yunnan Province by ArcGIS, a Geographic Information System (GIS)software. Based on DEM, the spatial analysis and statistical function of GIS, the landscape patterns of populationdistribution of the selected minorities is described, and 4 sub-regions are divided in the Nujiang River basin of YunnanProvince while the features and disparity of landscape pattern and its forming mechanism are discussed, along withhistorical and archaeological data. The conclusions are as follow: (1) The ethnic distribution is mosaic in the matrix ofother racial distribution, and have a distinct spatial correlation. (2) For the difference in cultivation between differentnationalities, certain nationality lived in the area suitable for production mode of its own and coincident with appropriategeographical setting. (3) The spatial distribution of settlement spots of the minorities is controlled by the convenience ofwater supply. The landscape pattern of ethnic distribution is closely relative to natural environment.展开更多
This paper presents a study on the gravityinduced rock slope deformation observed along the Nujiang River in China. We performed a comprehensive field investigation and analysis to identify the deformation pattern of ...This paper presents a study on the gravityinduced rock slope deformation observed along the Nujiang River in China. We performed a comprehensive field investigation and analysis to identify the deformation pattern of the slope and its triggering factors. Moreover, a geologicalevolutionary model was developed, and it considers the effects of river incision and rock mass degradation caused by weathering and simulates the mechanisms underlying the initiation and progression of the slope deformation. The results support the proposed failure mechanism in which fractures within the slope are induced by rock mass degradation caused by weathering. Importantly, the modeling reveals that compressional deformation at the toe of the slope results in a tensile failure in the upper portion of the slope, demonstrating that the rock mass in the slope toe is the key factor inducing slope deformation. This analysis of slope deformation and its spatial and temporal correlations with rock weathering and river incision reveal the main triggering factors that control the evolution of the studied slope and provide insights into the deformation process.展开更多
The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before t...The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before the M_S8. 0 Wenchuan earthquake is studied based on the analysis of the interference. The short-impending anomaly of the body strain deformation is considered to be reliable. The anomaly characteristics conclude:( 1) The trend anomaly as extensional change of the body strain deformations on a quasi 1 year time scale before the Wenchuan earthquake was recorded, and the accumulative amount was about 4000 × 10^(-9). Correspondingly,the short-term precursor of earthquake was manifested as an extensional abrupt change.( 2) The extensional intermittent anomalous abrupt change was recorded by body strainmeters between March1 and May 7 in 2008.( 3) Four compressional abrupt changes were recorded in the intermittent distortions recorded between April 13 and May 11.( 4) High frequency components were increased in the distortion process in May 1 to 3,5,7,and 9 to 12,caused by slow earthquakes before the Wenchuan earthquake according to wavelet analysis. The abnormal phenomena are summarized and the mechanics discussed in this paper. Strain solid tide distortions in body strain observations,the continuous repeated extensional and compressional abrupt changes accompanying these distortions,and the increase of high frequency components can be regarded as the index of short term and impending earthquake prediction,based on analysis of interference factors such as air pressure and water level.展开更多
基金Supported by the National Natural Science Foundation of China(42221002,42171432)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)the Fundamental Research Funds for the Central Universities.
文摘The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevita-bly affected by the orbiter attitude jitter.Therefore,it is necessary to conduct preliminary research on the stereo mapping camera equipped on lunar orbiter before launching.In this work,an imaging simulation method consid-ering the attitude jitter is presented.The impact analysis of different attitude jitter on terrain undulation is conduct-ed by simulating jitter at three attitude angles,respectively.The proposed simulation method is based on the rigor-ous sensor model,using the lunar digital elevation model(DEM)and orthoimage as reference data.The orbit and attitude of the lunar stereo mapping camera are simulated while considering the attitude jitter.Two-dimensional simulated stereo images are generated according to the position and attitude of the orbiter in a given orbit.Experi-mental analyses were conducted by the DEM with the simulated stereo image.The simulation imaging results demonstrate that the proposed method can ensure imaging efficiency without losing the accuracy of topographic mapping.The effect of attitude jitter on the stereo mapping accuracy of the simulated images was analyzed through a DEM comparison.
基金supported by China Geological Survey Northeastern Tarim Aeromagnetic and Aerogravity comprehensive survey project(No.12120115039401)
文摘Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods may generate analytical singularities for conditions of undulating terrain. Based on basic geomagnetic field theories, in this study an improved magnetic field expression is derived using an integration method of variable substitution, and all singularity problems for the entire space without a source are discussed and solved. This integration process is simpler than that of previous methods, and final integral results with a more uniform form. AT at all points in the source-flee space can be calculated without requiring coordinate transformation; thus forward modeling is also simplified. Corresponding model tests indicate that the new magnetic field expression is more correct because there is no analytical singularity and can be used with undulating terrain.
基金supported by the Public Welfare & Safety Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant No. 2012M3A2A1050979)
文摘This paper describes a geographic information system(GIS)-based method for observing changes in topography caused by the initiation, transport, and deposition of debris flows using highresolution light detection and ranging(LiDAR) digital elevation models(DEMs) obtained before and after the debris flow events. The paper also describes a method for estimating the volume of debris flows using the differences between the LiDAR DEMs. The relative and absolute positioning accuracies of the LiDAR DEMs were evaluated using a real-time precise global navigation satellite system(GNSS) positioning method. In addition, longitudinal and cross-sectional profiles of the study area were constructed to determine the topographic changes caused by the debris flows. The volume of the debris flows was estimated based on the difference between the LiDAR DEMs. The accuracies of the relative and absolute positioning of the two LiDAR DEMs were determined to be ±10 cm and ±11 cm RMSE, respectively, which demonstrates the efficiency of the method for determining topographic changes at an scale equivalent to that of field investigations. Based on the topographic changes, the volume of the debris flows in the study area was estimated to be 3747 m3, which is comparable with the volume estimated based on the data from field investigations.
文摘Static effort of rock mass very rarely causes of rock burst in polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or sliding in roof layers above the exploited panel in coal seam, sometime in a distance from actual exploitation. Sliding, as a rule occurs in fault zone and tremors in it are expected, but monolithic layer rupture is very hard to predict. In a past few years a practice of analyzing state of deformation in high energy seismic tremors zones has been employed. It let gathering experience thanks to witch determination of dangerous shape of reformatted roof is possible. In the paper some typical forms of roof rocks deformations leading to seismic tremor occurrence will be presented. In general these are various types of multidirectional rock layers bending. Real examples of seismic events and rock bursts will be shown.
基金Financial support for this work,provided by the National Basic Research Program of China(No.2006 CB202300),
文摘In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.
基金Under the auspices of National Natural Science Foundation of China(No.U0833002)National Science and Technology Support Program of China(No.2012BAC07B05)
文摘Phosphorus fractions and adsorption-release characteristics of sediments in the Zhujiang （Pearl） River estuary wetland were investigated. Results showed that the total phosphorus （TP） content in surface sediments ranged from 648.9 mg/kg to 1064.0 mg/kg; inorganic phosphorus （IP） was the major fraction of TP and ranged from 422.5 mg/kg to 643.9 mg/kg. Among the inorganic phosphorus, the main fractions were phosphorus bound to A1 and Fe （Fe/A1-P）, and calcium-bound phosphorus （Ca-P）, accounting for 23%-42% and 21%-67% of IP, respectively. The vertical distribution of TP contents were significantly positive correlated with organic phosphorus （Org-P） and Fe/A1-P contents. The bio-available phosphorus contents in vertical sediments varied from 128.6 mg/kg to 442.9 mg/kg, mainly existed in Fe-AI/P fraction, and increased from the bottom to top sediments. The transport of phosphorus in sediment-water in- terface was controlled by the soil characteristics. The active Fe and A1 content was considered as the main factor that determines adsorp- tion capacity in vegetated marsh wetland. The P buffering capacity of the sediments in vegetated marsh wetland was greater than that in mudflat wetland. The potential risk of eutrophication in the study area is high. Reducing terrestrial phosphorus discharge and preventing the sediment Fe/A1-P release to the interstitial water are the possible solutions to reduce the risk of eutrophication in estuary wetlands, and planting vegetation in estuary wetland can also reduce the release of phosphorus in surface sediment.
基金Financial support for this research, provided by the National Natural Science Foundation of China (Nos.50804020 and 50974070)the Doctor Initial Fund of Liaoning Provincial Science and Technology Department (No.20081103)the Key Laboratory Fund of Liaoning Province (No. LS2010074)
文摘In order to investigate the surface deformation caused by coal mining and to reduce environmental damage, more accurate information of dynamic subsidence basins, caused by coal mining, is needed. Based on theological theory, we discuss surface deformation mechanism of dynamic subsidence on the assumption that both the roof and the coal seam are visco-elastic media, put forward the idea that the principle of surface deformation is similar to that of roofs, except for their parameters. Therefore, a surface deforma- tion equation can be obtained, given the equation of the roof deformation derived.from using a HIM rhe- ological model. In the end, we apply the equation of surface deformation as a practical subsidence prediction in a coal mine. Given the theologic properties of a rock mass, the results of our research of a dynamic subsidence basin can predict the development of surface deformation as a function of time, which is more important than the ultimate subsidence itself. The results indicate that using rheological theory to calculate the deformation of a dynamic subsidence basin is suitable and provides some reference for surface deformation of dynamic subsidence basins.
文摘Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. From the spectral analysis of the results, we can see that the periods of displacements are 12 months and the semi-periods are 6 months. The results also show that the maximum seasonal displacements can reach 20 mm and even larger. The covariance analyses and significance tests show that the coefficients of 96 percent of the stations are significant at the 0.1 significance level. The results show that one of the reasons of the vertical crustal displacements is the changing surface fluid loads.
基金sponsored by the important projects of Yunnan Province,entitled"The regularity of strong earthquake activities and the plate margindynamic mechanism on the eastern margin of the Qinghai-Tibet plateau"(2010CC006)"Study on relationship between evolutionary dynamics of geophysical and geochemistry field and strong seismic activity in Yunnan"(JCYB200806015)
文摘In this paper, using focal mechanism solutions of moderate-strong earthquakes in Yunnan and its adjacent areas, and based on the statistical analysis of the parameters of focal mechanism solutions, we discussed in detail the earthquake fault types and the characteristics of the modern tectonic stress field in the Yunnan region. The results show that most moderate-strong earthquakes occurring in the Yunnan region are of the strike-slip type, amounting to 80% of the total. Normal faulting and normal with strike-slip and reverse and reverse with strike-slip earthquakes is almost equivalent in proportion, about 8% each. The tectonic stress field of the Yunnan region is near-horizontal, and the dips of earthquake fault planes are large. There are three main dynamic sources acting on the Yunnan region: one is the NE, NNE and NNW-directed acting force from Myanmar, Laos and Vietnam; the second is the SE-SSE directed force from the Sichuan and Sichuan-Yunnan rhombus block and the third is the NW-NNW directed force from the South China block. These three acting forces have controlled the faulting behavior of the main faults and the characteristics of strong earthquake activity of Yunnan and its adjacent regions.
文摘Each nationality has formed unique ethnic culture in the long history. Ethnic culture is spatially reflected byethnic distribution. The distribution of nationalities is influenced by ethnic history, culture, society and religion, alsoaffected by regional physical setting. This paper analyzes the relationship between ethnic distribution pattern and naturalsetting with contrast analytical method. The digital elevation model (DEM) is established on basis of contour map on ascale of 1:250,000 in the Nujiang River basin, Yunnan Province by ArcGIS, a Geographic Information System (GIS)software. Based on DEM, the spatial analysis and statistical function of GIS, the landscape patterns of populationdistribution of the selected minorities is described, and 4 sub-regions are divided in the Nujiang River basin of YunnanProvince while the features and disparity of landscape pattern and its forming mechanism are discussed, along withhistorical and archaeological data. The conclusions are as follow: (1) The ethnic distribution is mosaic in the matrix ofother racial distribution, and have a distinct spatial correlation. (2) For the difference in cultivation between differentnationalities, certain nationality lived in the area suitable for production mode of its own and coincident with appropriategeographical setting. (3) The spatial distribution of settlement spots of the minorities is controlled by the convenience ofwater supply. The landscape pattern of ethnic distribution is closely relative to natural environment.
基金Supported by the National Natural Science Foundation of China(Grant Nos. 41521002,41572283 and 41130745)supported by the Funding of Science and Technology Office of Sichuan Province (Grant Nos. 2015JQ0020)
文摘This paper presents a study on the gravityinduced rock slope deformation observed along the Nujiang River in China. We performed a comprehensive field investigation and analysis to identify the deformation pattern of the slope and its triggering factors. Moreover, a geologicalevolutionary model was developed, and it considers the effects of river incision and rock mass degradation caused by weathering and simulates the mechanisms underlying the initiation and progression of the slope deformation. The results support the proposed failure mechanism in which fractures within the slope are induced by rock mass degradation caused by weathering. Importantly, the modeling reveals that compressional deformation at the toe of the slope results in a tensile failure in the upper portion of the slope, demonstrating that the rock mass in the slope toe is the key factor inducing slope deformation. This analysis of slope deformation and its spatial and temporal correlations with rock weathering and river incision reveal the main triggering factors that control the evolution of the studied slope and provide insights into the deformation process.
基金funded by the Three-in-One Project of Earthquake Monitoring,Forecasting and Scientific Research of China Earthquake Administration:Statistical Research on Earthquake Cases of Short-impending Anomalies of Sacks Body Strain(154201)Operation and Maintenance of the Shisanling(Ming Tombs)Seismic Station(40417600105)
文摘The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before the M_S8. 0 Wenchuan earthquake is studied based on the analysis of the interference. The short-impending anomaly of the body strain deformation is considered to be reliable. The anomaly characteristics conclude:( 1) The trend anomaly as extensional change of the body strain deformations on a quasi 1 year time scale before the Wenchuan earthquake was recorded, and the accumulative amount was about 4000 × 10^(-9). Correspondingly,the short-term precursor of earthquake was manifested as an extensional abrupt change.( 2) The extensional intermittent anomalous abrupt change was recorded by body strainmeters between March1 and May 7 in 2008.( 3) Four compressional abrupt changes were recorded in the intermittent distortions recorded between April 13 and May 11.( 4) High frequency components were increased in the distortion process in May 1 to 3,5,7,and 9 to 12,caused by slow earthquakes before the Wenchuan earthquake according to wavelet analysis. The abnormal phenomena are summarized and the mechanics discussed in this paper. Strain solid tide distortions in body strain observations,the continuous repeated extensional and compressional abrupt changes accompanying these distortions,and the increase of high frequency components can be regarded as the index of short term and impending earthquake prediction,based on analysis of interference factors such as air pressure and water level.
