贵州省草海表层水体和沉积物间隙水中汞的含量和形态分布初步研究

运用金汞齐-冷原子荧光光谱法(CVAFS)和气相色谱技术(GC),对贵州省草海不同水文季节(枯水期和丰水期)表层水中汞的各种赋存形态,包括总汞(HgT)、溶解态汞(HgD)、活性汞(HgR)、颗粒态汞(HgP)、总甲基汞(MeHgT)、溶解态甲基汞(MeHgD)和颗粒态甲基汞(MeHgP)以及沉积物间隙水剖面中的溶解态总汞和甲基汞含量进行了测定.结果显示:草海表层水体总汞浓度为1.7-9.0ng/L,活性汞浓度为0.06-1.4ng/L,总甲基汞浓度为0.11-0.67ng/L.沉积物间隙水中溶解态汞浓度为8.6-39.6ng/L,溶解态甲基汞浓度为0.11-4.9ng/L.实验数据表明,草海湖水以溶解态汞为主,其占总汞的比例为枯水期87%,丰水期51%,溶解态汞与总汞呈显著相关(丰水期P<0.01;枯水期P<0.05),颗粒态汞与总汞也呈显著相关(丰水期P<0.01;枯水期P<0.05).溶解态甲基汞与总甲基汞呈显著相关(丰水期P<0.01;枯水期P<0.05),表明溶解态甲基汞控制总甲基汞的分布.沉积物间隙水溶解态汞与溶解态甲基汞浓度明显高于上覆水体,表明沉积物为草海湖水中汞的一个重要来源.     

汶川地震前的b值变化

Gutenberg-Richter定理给出了地震频度随震级的分布特征.大量研究表明频度-震级关系的斜率（b值）在大地震孕育的过程中会出现减小.为了考察b值在汶川地震孕育过程中的时间演化特征,本文尝试基于破裂断层选取研究区域,考察了2000年1月至2008年4月间,汶川地震（M_S8.0）破裂区的地震活动性,并对该区域b值的变化进行了探讨.结果表明,在2005年中至2006年底,地震月频度及季度频度有一个较明显的下降.b值从2002年始至地震前呈现出一个长期趋势性减小;在地震前约半年,出现快速、显著的下降.b值的这一时间变化特征与其他研究者报道的日本东北M_W9.0级地震前的b值变化特征具有很高相似性,可能反映了大地震准备过程中的应力变化.以上结果有益于认识和理解大地震孕育演化过程,同时也表明b值在中长期地震灾害评估中具有潜在价值.     

汶川地震断裂带科学深钻WFSD-3附近上地壳S波分裂特征

为配合汶川地震断裂带科学钻探工程(WFSD),中国地震局地球物理研究所在四川省绵竹市天池乡和灌县—安县断裂附近分别架设了15套微震仪器和17个短周期地震台.基于WFSD-3附近的微震、短周期和区域台网的固定台站记录的近震数据,通过横波窗内S波分裂计算,得到其上地壳各向异性参数,即快波偏振方向和慢波的时间延迟,并分析了研究区的上地壳各向异性特征.结果显示,研究区大部分区域的快波偏振方向为NE向,与龙门山断裂带走向一致,但在研究区微震台阵布设小区域内,快波偏振方向表现出东西分区特征,东部为NE向,西部为NW向.上地壳各向异性主要是受到岩层中随应力分布排列的微裂隙和岩石或矿物结构的影响,研究区内快波偏振方向主要表现为NE方向,与断裂走向一致,反映了研究区上地壳各向异性主要受控于结构控制的各向异性,局部区域的快波偏振方向为NW向,与区域最大主压应力方向一致,说明区域应力场对研究区上地壳各向异性也有影响.通过分析微震台阵的归一化时间延迟随时间的变化情况可以反映区域应力场的变化情况.微震台阵的慢S波时间延迟在2012、2013年较为离散,在2014年有收敛的趋势,反映了强震后区域应力场逐渐稳定的趋势.     

SIMULATION STUDY OF ROAD-CUT EFFECTS ON SLOPE STABILITY

Landslides and rock falls along the highway are common geological hazards in Southwest China. As an influencing factor on potential landslides behavior, roads or distance to roads have been successfully used in landslide susceptibility assessments in mountainous area. However, the relationship between the road-cut and the slope stability is not clear. Therefore, we performed two-dimensional slope stability calculation using the general limit equilibrium (GLE)method incorporated in the software SLOPE/W of GeoStudio for stability analysis of slopes. Our studies show that the man-made roads influence on the slope stability mainly exists in two ways:One is to create a new steep slope, which will result in rock falls and shallow landslides along the roads; the other is to influence the stability of the original slope, which will result in comparatively huge landslides. For the latter, our simulation study reveals that the road location, namely at which part of a natural slope to construct a road is important for the slope stability. For a natural slope with a potential slip surface, if a road is constructed at or near the slope toe where the potential slip surface surpasses, it will greatly degrade the slope's factor of safety (Fs) and make the slope unstable; however, if a rode-cut is near the top of the slope, it will increase the slope's Fs and make the slope more stable. The safety location is different for different slope angle, steeper slope needs a higher location for a safety road-cut in comparison with gentle slopes. Moreover, the slope stability decreases when loading a seismic force and it varies with the slope angle. Firstly, the Fs decreases when the slope angle increasing, and when the slope angle reaches 45°, the Fs then becomes greater with the slope angle increasing.     

THE APPLICATION OF MINIATURE UNMANNED AERIAL VEHICLE IN 25 NOVEMBER 2016 ARKETAO MW6.6 EARTHQUAKE

In order to complete the field investigation to the 25 November 2016 Arketao M_W6.6 earthquake, ultra-low altitude remote-sensing data were obtained from miniature unmanned aerial vehicle. The surface rupture surveying has important significance for earthquake research. This paper selects the macro-epicenter of Arketao as the study area. The pictures were obtained with DJI Phantom 3 professional input into the software, the Digital Elevation Model (DEM), Digital Orthophoto Map (DOM) were acquired based on photogrammetry method using the overlapped optical remote-sensing images of UAV. Using these data, we can identify surface ruptures that have vertical dislocation. We selected six feature points and drew the elevation profile. In the elevation profile map, we chose smooth part of the surface rupture sides and obtained the trend line. A stable point in the surface rupture was selected and the abscissa of the point was taken into the equation of two straight lines. Then subtracting the results of the two equations, we can get the vertical dislocation of the surface rupture. On this basis, we chose six feature points and determined their vertical dislocation, which are between 4.4cm and 10.4cm. What's more, taking Bulungkou Xiang in Xinjiang Uygur Autonomous Region for example, we speculated some surface ruptures that have vertical dislocation. It can provide a new method for identifying surface rupture in the field. In addition, we get DEM data of the Bulunkou area where ambient conditions are very poor, by using miniature unmanned aerial vehicle and taking 255 photos. Putting those photos into the EasyUAV software, we got the area digital elevation of 2cm resolution. Comparing these data with RTK data, we summarized some practical problems and solutions in the practical operation and evaluated the accuracy of miniature unmanned aerial vehicle data. The Pearson Correlation Coefficient is 0.996 6. In terms of absolute elevation, the average result of UAV and RTK differs by 156.96m. In terms of relative elevation, the average result of UAV and RTK differs by 9.74m. Compared with the previous test of Pishan County, there is a notable divergence in the results. It shows that the data accuracy will be affected to some extent in the cold weather in high elevations. The specific impact needs further exploration.     

基于参考台的盲源分离法在抑制地磁场近场噪音中的应用研究

随着城市建设的不断发展,地磁场观测受到的人文干扰越来越严重.汽车、地铁、高铁等产生的近场噪音造成了地磁脉动等空间场源信号难以被精确观测,严重影响了地磁观测资料的实际使用价值.因此抑制这些近场噪音、提取空间场源信号具有科学意义和应用价值.本研究将远场参考法和盲源信号分离法相结合,提出了一种能有效分离空间场源信号和近场噪音的方法.首先,基于仿真分析,我们准确分离了不同特征的源信号,阐明了此方法的有效性.然后,我们将该方法应用于日本千叶地区受电车干扰较为严重的实际磁场观测数据,并选用数据质量较高的KAK国际基准台作为远场参考,实现了地磁脉动和电车干扰信号的分离,并在此基础上对观测台站的近场噪音进行了抑制.这些结果表明基于参考台的盲源信号分离法在抑制近场噪音、提取地磁场信号中是有效的,可能在电磁法勘探中具有潜在的应用价值.     

GPS精密单点定位中精密星历和钟差的内插算法选取

利用了IGS中心给出的精密星历,计算了几种插值以及拟合算法,分析和比较了插值与拟合的质量与运算效率,基于精密单点定位软件验证与对比了其精度。     

极化SAR影像分类方法研究

采用不同的分类方法对荷兰Flevoland地区全极化数据进行分类,讨论了各分类方法存在的问题,通过比较得出基于复Wishart分布的最大似然监督分类的效果较好。     

TOPEX/Poseidon卫星监测博斯腾湖水位变化及其与NINO3 SST的相关性分析

利用TOPEX/Poseidon(T/P)卫星10年（1992~2002）监测博斯腾湖水位变化的GDR数据,经过数据的地球物理改正、编辑、约化和滤波后,分别采用小波分析和傅里叶分析得到了博斯腾湖水位变化的平均周期为1034d,363d,182d和47d。季节性变化是湖泊水位变化的主项,利用最小二乘法得到了周年振幅为0.7196m,半年振幅为0.5322m,因此季节性变化的主周期是周年,次周期是半年。博斯腾湖水位变化变化趋势为0.2012m/a,说明在全球气候变暖趋势下,博斯腾湖水位在升高。由博斯腾湖月水位变化的时间序列与NINO3 SST进行相关性分析,发现在NINO3 SST 发生6个月后,博斯腾湖月水位变化序列与NINO3 SST数据相关性最大(-0.2784),表明厄尔尼诺事件对我国西部气候影响的具有一定的滞后性。     

出租车经验知识建模与路径规划算法

以出租车采集的浮动车数据,研究出租车司机道路选择的经验和规律,建立出租车司机道路寻径的经验知识模型,将城市交通道路网按该知识模型分成不同等级的经验路网;在此基础上提出基于经验知识的交通道路寻径算法,并以武汉市交通路网和浮动车为实验数据,将本文提出的道路寻径算法与传统的最短路径规划算法进行比较,实验结果表明在起止点相同的情况下,本文选择的路径较好地保持了道路等级的一致性和连贯性,明显减少通行时间,更符合自主出行的认知.