Mean slope-angle frequency distribution and size frequency distribution of landslide masses in Higashikubiki area, Japan

Landslide mass size frequency distributions and mean slope-angle frequency distributions were calculated for slump, slide, and creep type landslides in the Higashikubiki area. Mean slope-angle frequency distributions closely approximated Weibull distributions. Size frequency distributions show power-law dependencies. Both can be explained by modeling landslides as linked uniform blocks in tensile force. Power coefficients for size frequency distributions were 2.01–2.32 (approximation to power functions) or 2.10–2.24 (approximation to Pareto distributions).     

我国数字填图技术研究现状与发展趋势

数字填图系统(RGMAP)是中国地质调查局研发的,用来进行区域地质调查工作的专业软件.通过4幅150000和10幅1250000数字填图试点应用,使数字填图系统已臻于完善,为中国地质调查局全面推广数字填图方法奠定了良好的基础.野外数据采集数字化,使得地质调查数据实现了一体化的描述、组织、综合、管理及资源的统一描述、再现和集成.建立个性化的多用户,多目标的社会化服务体系,是今后地质调查主流程信息化的主要任务和目标.     

~(40)Ar/~(39)Ar Dating of Deformation Events and Reconstruction of Exhumation of Ultrahigh-Pressure Metamorphic Rocks in Donghai, East China

Recent investigations reveal that the ultrahigh-pressure metamorphic (UHPM) rocks in the Donghai region of East China underwent ductile and transitional ductile-brittle structural events during their exhumation. The earlier ductile deformation took place under the condition of amphibolite facies and the later transitional ductile-brittle deformation under the condition of greenschist facies. The hanging walls moved southeastward during both of these two events. The 40Ar/39Ar dating of muscovites from muscovite-plagioclase schists in the Haizhou phosphorous mine, which are structurally overlain by UHPM rocks, yields a plateau age of 218.0±2.9 Ma and isochron age of 219.8Ma, indicating that the earlier event of the ampibolite-facies deformation probably took place about 220 Ma ago. The 40Ar/39Ar dating of oriented amphiboles parallel to the movement direction of the hanging wall on a decollement plane yields a plateau age of 213.1±0.3 Ma and isochron age of 213.4±4.1 Ma, probably representing the age o     

Late Caledonian Ductile Thrusting Deformation in the Central East Kunlun Belt, Qinghai, China and Its Significance: Evidence from Geochronology

A high-angle ductile thrusting deformation with top-to-the-north movement penetratively developed in the Proterozoic-Early Paleozoic metamorphic rocks along the Central East Kunlun belt. The deformed rocks suffered epidote-amphibolite facies metamorphism. On the basis of our previous study, we present more data in this paper to further support that the ducdle thrust deformation occurred in the later Caledonian and more detailed information about the deformation. A zircon U-Pb concordant age of 446±2.2 Ma of a deformed granodiorite in the ductile thrust zone was obtained and can be interpreted as the lower limit of the deformation. A syntectonically crystallized and also strongly deformed hornblende Ar/ Ar dating gives an Ar/Ar plateau age of 426.5±3.8 Ma, which represents the deformation age. A strongly orientated muscovite gives an Ar/Ar plateau age of 408±1.6Ma, representing the cooling age after the peak temperature, constraining the upper limit of the ductile thrust deformation. This ductile thru     

基坑支护结构水平变形预测的遗传神经网络方法

采用遗传算法和误差反向传播算法相结合的混合算法来训练前馈人工神经网络,先用遗传学习算法进行全局训练,再用BP算法进行精确训练。就遗传算法过程中的选择、变异进行了探索,提出了用BP网络训练产生变异的遗传算法。作为实例,将该方法应用于预测基坑支护结构水平变形中。结果表明,该方法有收敛速度较快、预测精度高等优点。