岫岩陨石撞击坑的速度结构和抗震性能分析

岫岩陨石撞击坑位于辽东半岛北部低山丘陵地区,直径1.8km,保存完好。由于陨石的撞击和此后的沉积作用在坑内形成了特殊的地貌、地质和地球物理环境,使坑内与坑外的介质在速度方面存在差异,尤其是湖相沉积的软弱淤泥层使得坑底上建造的房屋就像躺在一张巨大的海绵垫上一样,使人们常常感到有微震发生,表明坑底的软弱地层对地面的震动产生了放大作用,严重地影响了地基的稳定性,从而影响到地面建筑物的抗震性能。本文采用高分辨折射探测方法,获得了陨石坑内的速度结构和软弱地层的分布,分析了陨石坑地基的抗震性能,为坑内地基和地面建筑物的地震危险性评价提供了可靠的基础资料。     

Spatiotemporal variation and driving forces of reference evapotranspiration in Jing River Basin,northwest China

Evapotranspiration is an important component of the hydrological cycle, which integrates atmospheric demands and surface conditions. Research on spatial and temporal variations of reference evapotranspiration (ET_o) enables understanding of climate change and its effects on hydrological processes and water resources. In this study, ET_o was estimated by the FAO‐56 Penman–Monteith method in the Jing River Basin in China, based on daily data from 37 meteorological stations from 1960 to 2005. ET_o trends were detected by the Mann–Kendall test in annual, seasonal, and monthly timescales. Sensitivity coefficients were used to examine the contribution of important meteorological variables to ET_o. The influence of agricultural activities, especially irrigation on ET_o was also analyzed. We found that ET_o showed a decreasing trend in most of the basin in all seasons, except for autumn, which showed an increasing trend. Mean maximum temperature was generally the most sensitive parameter for ET_o, followed by relative humidity, solar radiation, mean minimum temperature, and wind speed. Wind speed was the most dominant factor for the declining trend in ET_o. The more significant decrease in ET_o for agricultural and irrigation stations was mainly because of the more significant decrease in wind speed and sunshine hours, a mitigation in climate warming, and more significant increase in relative humidity compared with natural stations and non‐irrigation stations. Changes in ET_o and the sensitivity coefficient of meteorological variables in relation to ET_o were also affected by topography. Better understanding of ET_o response to climate change will enable efficient use of agricultural production and water resources, which could improve the ecological environment in Jing River Basin. Copyright © 2015 John Wiley & Sons, Ltd.     

Climate projections of spatial variations in coastal storm surges along the Gulf of Mexico and U.S. east coast

Using statistically downscaled atmospheric forcing, we performed a numerical investigation to evaluate future climate's impact on storm surges along the Gulf of Mexico and U.S. east coast. The focus is on the impact of climatic changes in wind pattern and surface pressure while neglecting sea level rise and other factors. We adapted the regional ocean model system(ROMS) to the study region with a mesh grid size of 7–10 km in horizontal and 18 vertical layers. The model was validated by a hindcast of the coastal sea levels in the winter of 2008. Model's robustness was confirmed by the good agreement between model-simulated and observed sea levels at 37 tidal gages. Two 10-year forecasts, one for the IPCC Pre-Industry(PI) and the other for the A1 FI scenario, were conducted. The differences in model-simulated surge heights under the two climate scenarios were analyzed. We identified three types of responses in extreme surge heights to future climate: a clear decrease in Middle Atlantic Bight, an increase in the western Gulf of Mexico, and non-significant response for the remaining area. Such spatial pattern is also consistent with previous projections of sea surface winds and ocean wave heights.     

滑坡监测的自适应约束抗差滤波算法研究

在滑坡的动态监测中通常存在先验几何信息和物理信息,现有的滤波算法并不能够充分利用这些信息,为控制几何观测异常对形变参数估计的影响,提出一种利用滑坡力学状态信息的约束滤波模型.同时,利用约束方程获得有益信息,精确地确定测量的等价权,给出相应的自适应约束抗差滤波算法,并通过实例说明了带有约束的滤波算法更能提高状态参数估计的...     

地震应急快速触发响应系统的参数配置与用户分组管理

主要介绍了中国数字地震观测网络项目应急分项软件"地震应急快速触发响应系统"中的参数配置和用户分组管理2项重要的基础功能模块,详细阐述了这2项功能的具体实现方法和原理。     

东昆仑三道湾流纹英安斑岩锆石U-Pb年龄及其地质意义

东昆仑格尔木河西三道湾流纹英安斑岩构成火山通道侵出相,侵入到纳赤台群哈拉巴依沟组碎屑岩系中,其形成时代对于造山带火山作用的研究和限定哈拉巴依沟组地层时代均具有重要的意义。采用激光烧蚀多接收器电感耦合等离子体质谱(LA-MC-ICP MS)方法,对三道湾流纹英安斑岩进行了锆石U-Pb定年,结果表明,流纹英安斑岩中25个岩浆锆石206Pb/238U加权平均年龄为425.9 ± 2.6 Ma,它被解释为流纹英安斑岩的结晶年龄,说明三道湾次火山岩所代表的火山通道为早古生代造山晚期牦牛山组火山岩形成时的火山喷发中心之一,而非晚侏罗世次火山岩。野外地质关系和次火山岩年龄可以限定哈拉巴依沟组形成于中志留世之前。      

Multiscale anisotropic diffusion for ringing artifact suppression in geophysical deconvolution data

Ringing artifact degradations always appear in the deconvolution of geophysical data. To address this problem, we propose a postprocessing approach to suppress ringing artifacts that uses a novel anisotropic diffusion based on a stationary wavelet transform (SWT) algorithm. In this paper, we discuss the ringing artifact suppression problem and analyze the characteristics of the deconvolution ringing artifact. The deconvolution data containing ringing artifacts are decomposed into different SWT subbands for analysis, and a new multiscale adaptive anisotropic filter is developed to suppress these degradations. Finally, we demonstrate the performance of the proposed method and describe the experiments in detail.     

利用古温标恢复四川盆地主要构造运动时期的剥蚀量

地层剥蚀量是沉积盆地埋藏史和热史重建中一个关键的参数.本文利用石油钻井的系统古温标(Ro)资料,并结合多种恢复方法,得出四川盆地主要构造运动时期的剥蚀量.研究表明:加里东期,川东南剥蚀量较大,达2000m.东吴运动时期,川西南、川东南等距二叠纪玄武岩喷发区较近地区的剥蚀量较大,分别在260～450 m和800～900m:印支早期盆地整体遭受了抬升剥蚀作用,剥蚀厚度为100～500 m.印支中、晚期龙门山地区褶皱剥蚀,H1、Y1等钻井该时期的地层剥蚀量超过2000 m.燕山期周缘山系的继续隆升造成山前大范围地区的剥蚀:喜山期盆地周缘钻井的剥蚀量较大,在2000 m左右,而早期古隆起上的钻井如GJ、J13、Z12等钻井的地层剥蚀量则较小,在1000 m左右.可见,四川盆地不同地质时期及不同构造区位的剥蚀厚度都不尽相同,这一时空差异反映了构造运动对该区的差异影响.这一研究也表明,以系统的古温标资料(R_o)为基础,针对不同地质情况选用适当的反演方法并结合多种反演方法.能有效地恢复钻井在不同时期的剥蚀量.上述四川盆地各时期剥蚀地层厚度的恢复,对研究该区的构造、沉积和油气演化提供了基础数据.     

东南亚中南半岛地区黑色金属矿床谱系

东南亚中南半岛地区位于特提斯-喜马拉雅成矿带与环太平洋成矿带的交汇部位,具有丰富的富铁、优质锰、铬铁矿、钛铁矿等黑色金属资源。在系统收集和整理该区矿产地数据的基础上,建立了中南半岛5国（越南、老挝、柬埔寨、缅甸和泰国）的矿产地数据库,初步厘定了黑色金属矿床谱系,并对其找矿潜力进行了简要分析。     

Application of Fractal Models to Distinguish between Different Mineral Phases

Fractal modeling is demonstrated to be an effective and rapid tool to distinguish between mineral phases in rock samples. It supplements work that previously could be performed only by observing the interpenetrational or metasomatic phenomena between different minerals with the aid of mineralographic microscope. The Gejiu tin district in southwestern China was chosen as a study area for the recognition and characterization of the spatial distribution of two phases (Types I and II) of cassiterite. Vector patterns used for this study were extracted from digital photomicrographs and analyzed with the aid of MapGIS. Perimeter–area fractal dimension, cumulative number–area exponent, and shape index were determined in order to quantify geometrical irregularities and spatial cassiterite phase distribution characteristics. The results show that fractal dimensions based on area and perimeter are larger for crystals of Type I than for those of Type II. The mean shape index (SI) increases from 0.54 (Type I) to 0.64 (Type II), indicating an increase in regularity. The number–area exponent also increases from 0.88 to 1.15, indicating the smaller crystals of Type II. The cumulative number–shape index log–log plot shows two separate straight-line segments. One of these probably represents a background shape realized during the original process of natural crystallization, whereas the other likely represents anomalous shapes because of weathering or other superimposed processes. Two parallel lines can be constructed on the perimeter–area log–log plots. The upper line, with a larger intercept, represents crystals with lower SI. The lower line represents crystals with higher SI, indicating that the intercept provides a measure of the irregularity of grains. By combining the perimeter–area model with cumulative number–area plot and shape index, the two phases of cassiterite can be distinguished and characterized. One phase has fewer crystals of large size, and the other has smaller crystals. This difference can be explained by assuming that under higher-temperature conditions, the large cassiterite crystals formed earlier than the smaller crystals. Consequently, the large cassiterites underwent longer, high-intensive weathering than the small crystals so that their shapes became more irregular. The younger, more abundant small cassiterites retained their original regular shapes.