濮阳小震集中区地震重定位及发震构造分析

利用濮阳周边数字地震台网近十年的震相观测报告数据及3级以上地震事件的波形记录,基于人工地震宽角反射/折射剖面的速度模型,采用Hypo2000地震定位法对研究区内1级以上287次地震事件进行绝对定位。同时,以Hypo2000绝对定位结果为初始位置,对濮城镇附近约25 km范围内的153个一级以上地震进行双差相对定位,获得更为准确的相对位置关系。定位研究结果表明:重新定位后研究区的小震震丛在震中和震源深度剖面上均呈现出两个分支:主支地震群沿聊—兰断裂分布,由少数地震组成的分支则分布于黄河断裂东侧。结合深地震反射剖面解释结果,推断濮城镇小震震丛的发震构造主要以聊—兰断裂为主,西部少数地震分支的发震断层为黄河断裂带,同时小震活动亦与油田开采注水活动密切相关。     

Interpolation for geochemical surface reconstruction incorporating topographic catchment definitions

Geochemical surfaces are reconstructed by interpolating geochemical measurements obtained from stream-water and stream-sediment samples. The geographical region that influences (and therefore is represented by) the value of a geochemial sample is its topographic catchment area. However, standard convention is to treat and to record the stream sample in the database as a point location, and to reconstruct geochemical surfaces utilizing conventional point interpolation procedures. These interpolation procedures assume, generally, that a data point exerts geographical influence away from itself in all directions, and that influence declines with distance away from that data point. Conventional interpolation procedures are poorly suited for reconstructing geochemical surfaces from stream samples; they do not take into account the true geographic area that geochemical sample points represent (topographic catchments). In this paper we propose a method of interpolation which assumes that data points are representative of their topographic catchment areas. Experimental data indicates that a surface reconstruction procedure which preserves the areal character of geochemical samples provides results more meaningful than surfaces reconstructed using more conventional interpolation techniques.     

中国冬夏季气温和降水异常耦合关系的SVD与MEOF分析对比

以揭示中国冬、夏季气温、降水之间的同期耦合时空特征为例,比较了SVD与MEOF分析所得主要正交模的相关关系及均衡性,论证了SVD方法在揭示两个要素场序列互相关关系上的优越性。结果表明:1) SVD的分解对象仅包含反映两种要素场相关关系的信息,而MEOF还包含了两个要素场各自的自相关信息,前者分解对象更纯粹。2) MEOF和SVD揭示的气温和降水空间耦合模态正负异常分布大致相似,但相较SVD所揭示的耦合模态,MEOF分析的冬、夏季气温、降水主要正交模存在不均衡现象,即一个主要MEOF正交模往往侧重描述两种异常要素场中的一种,这种差异在冬季尤为突出。SVD方法揭示了中国冬、夏季同期气温、降水间局域高温少降水或低温多降水是二者主要异常配置,且相关性夏强冬弱。3)比较SVD、MEOF方法同序正交模的相关系数和均衡度发现,SVD多数正交模的相关系数较MEOF的更大、更稳定,且均通过显著性检验,MEOF的冬季部分正交模相关系数未通过显著性检验; SVD主要正交模的均衡性冬季优于MEOF分析、夏季优于(第一模态)或者接近于(第二、三模态) MEOF分析。故SVD方法是揭示两要素之间耦合关系的更好方法。     

黄渤海一次持续性海雾过程形变特征及其成因分析

2016年3月3—5日,渤海和黄海大部出现了一次大范围持续性的海上大雾天气过程。本文从卫星遥感监测上分析海雾在生成、发展和消亡三个阶段的形态演变特征。从海洋气象条件上分析了山东半岛东南近海没有海雾和海雾形态演变的原因。结果表明:(1)在海雾形成初期,在山东半岛东南海域有弱气旋性弯曲,大气层结不稳定,地面形势受低压影响,虽受偏南风控制,但湿度小,无水汽辐合,因此在山东半岛东南近海没有雾。(2)海雾的形成与低层的偏南暖湿气流有关,而这个偏南暖湿气流来源于西北太平洋,雾区对应着水汽辐合区,海气温差为0～1℃的区域与雾区吻合,在海雾发展成熟期,雾顶长波辐射导致雾体降温,出现气温低于海温的现象。(3)925～1000 hPa垂直风切变有利于海雾在逆温层内维持和垂直高度上的发展,形成有一定厚度的海雾。     

基于ECMWF产品福建省前汛期短时强降水预报方法

利用2014—2016年福建省1605个自动气象站逐时降水资料和ECMWF全球模式细网格预报产品,分析福建省前汛期短时强降水发生背景下模式预报物理量的分布特征,并基于阈值判定的方法建立短时强降水预报模型。结果表明:福建省内陆县市前汛期短时强降水发生频次较高,沿海县市发生频次低,且日变化特征表现出双峰结构。箱型图差异指数（I_bd）在评估相关变量对于区分短时强降水发生与否的敏感程度有较好的作用,比湿、整层可降水量等水汽变量I_bd最为显著,K指数、对流有效位能等变量的I_bd仅次于水汽变量,说明模式预报变量对于预测短时强降水有较好的表征作用。针对短时强降水事件的物理量集合,采用剔除异常值后的最小值作为判定阈值,通过训练集分析结果客观订正对流有效位能和3 h降水量两个高I_bd变量的阈值,建立潜势预报模型。对于福建省西部的关键区,检验集白天时段12 h时间分辨率预报TS评分可达0.5,夜间时段约为0.3。对于福建省进行分区建模预报,检验集预报结果显示白天时段比夜间准确率高、内陆县市比沿海县市准确率高。     

东部三大经济区城市流动人口的多维度社会融入及其地区差异

以流动人口集中的京津冀、长三角和珠三角三大经济区35个城市2012年流动人口动态监测数据为基础,采用均方差权值法,综合经济、社会、心理、制度和公共服务5个维度构建衡量流动人口社会融入的指标体系,在此基础上计算和比较了三大经济区及其35个城市流动人口各维度社会融入指标和社会融入综合水平得分及其地区差异。研究结论显示,社会融入综合水平得分由高到低依次是京津冀、长三角、珠三角。同一地区流动人口的融入状况在各个维度不均衡,京津冀地区流动人口社会维度的融入程度最高,制度维度融入程度最低;长三角地区流动人口的心理维度融入居前列,但社会维度融入位列最后;珠三角地区流动人口的社会维度融入程度最高,公共服务维度融入不足。此外,就整体而言,三大地区流动人口的工作强度大、交往对象固化于流动人口、在流入地长期居住意愿多数仍处于举棋不定的状态;三大地区都存在落实居住证/暂住证制度和流动人口享有城镇医保等方面较为薄弱等诸多问题并共同制约着流动人口真正融入流入城市。为此,需要在政策制定中予以关注。     

中国人类福祉地区差距演变及其影响因素——基于人类发展指数(HDI)的分析

应用空间基尼系数、泰尔系数分解及面板模型等方法,对1995-2013年中国人类福祉地区差距及其影响因素进行分析,结果显示：①1995-2013年中国人类福祉省际差距整体趋于缩小。其中,“九五”时期不断缩小,“十五”时期波动变化,“十一五”时期快速缩小,“十二五”时期趋同发展;②四大区域之间的人类福祉差距是最主要的差距,但其贡献率总体呈递减趋势,而区域内人类福祉省际差距的贡献率呈递增趋势。西部地区人类福祉的省际差距最大但降幅明显,东部地区人类福祉的省际差距先扩大后降低,中部、东北地区人类福祉省际差距相对较小且不断缩小;③中国人类福祉地区差距和城乡收入差距同向扩大。加快经济发展、增加教育经费投入均可提高中国各省的人类福祉水平,但也可能扩大地区差距。提高卫生经费占比的增长率可降低中国人类福祉水平,但却能有效缩小中国地区之间的福祉差距。提高人均社会保障支出和人均转移支付,既能提高中国各省区的人类福祉水平,又可起到促进地区之间福祉均衡作用。     

Site effects modelling applied to the slope affected by the Suusamyr earthquake (Kyrgyzstan, 1992)

In 1992, a large magnitude earthquake (Ms = 7.3) hit the northern part of the Kyrgyz Tien Shan range where it triggered rockslides and many debris slides or flows. One of these mass movements occurred on the Chet–Korumdy ridge located in the Suusamyr Basin. It consists of a multi-rotational debris slump in its upper part that turned into a debris flow in its lower part. Involving arenitic material overlying silty clays, it has a volume of about 0.5 to 1.10⁶ m³, a maximum thickness of 40 m and a run-out of 200 m. The field observations and measurements carried out on this slope suggest that local amplification effects could have contributed to the initiation of the seismic failure. To test this hypothesis in the lack of instrumental evidence of local ground-motion recordings, we conducted a sensitivity study of site effects based on a numerical analysis in the visco-elastic domain with a two-dimensional finite difference code. Varying the topography and the geology of the investigated slope, topographic site effects are found to be less important than geological site effects which are controlled by the contrast of impedance between the surface materials and the bedrock. The geometry of the low-velocity surface layer has also an influence on site effects, which is often difficult to be distinguished from pure topographic effects. Considering all modelling results, we conclude that site amplifications alone cannot have triggered the Suusamyr landslide during the 1992 earthquake. The static slope stability analyses done in previous studies revealed that the Suusamyr failure neither can have a purely static origin. Even if the water table is very high within the arenite layer, only a minor failure develops in the lower part of the slope. Therefore, we believe that the triggering of the Suusamyr landslide is a consequence of pore pressure build up in areas characterized by significant ground-motion amplifications.     

Evaluating cut slope failure by numerical analysis—a case study

Slope failure is very common phenomenon in hilly regions, especially in young techno active mountainous like Himalayas. It is hazardous because of the accompanying progressive movement of the slope-forming material. In order to minimize the landslide effects, slope failure analysis and stabilization requires in depth understanding of the process that governs the behavior of the slope. The present article mainly deals with the analysis of the stability of road cut slopes of Rudraprayag Area, Uttarakhand, India. The area experiences local as well as regional slides every year. Extensive field study was carried out along the road cut slopes. Laboratory experiments were conducted to determine the various Physio-mechanical properties of rock mass. These properties have been used as input parameters for the numerical simulation of slope using FLAC3D (Fast Lagrangian Analysis of Continua) including geological discontinuities. The computed deformations and the stress distribution along the failure surface are compared with the field observations. The study indicates that the overall slope is unstable except at the location E where slope is critically stable. The effects of instability have been thoroughly considered and remedial measures have been recommended.