河北平原地震带的现今活动性分析

根据近41年的现代地震资料,利用地震活动性参数组合、b值空间分布、断裂带分段,并结合历史强震构造背景的综合分析方法,分析河北平原地震带各分段现今地震活动习性和地震危险性.研究结果表明：河北平原地震带存在7个具有不同现今活动习性的分段,其中,唐山—迁安段和东明—阳谷段处于低b值、高应力状态,属于大震后晚期余震活跃或断层震后调整运动结果;昌平—宝坻、天津—肃宁段、新河段、邯郸—磁县及汤西段断层面现今活动习性均处于相对低应力下的频繁或稀疏小震滑动.因此,河北平原地震带未来短期内发生强震的可能性较小.     

Experimental study on the viscoelastic behaviors of debris flow slurry

The rheological properties of most liquid in nature are between liquids and solids,including both elastic changes and viscosity changes,that is socalled "viscoelastic".Dynamic oscillatory test was used to quantitatively study the distinct viscoelastic behaviors of debris flow slurry in the shear stress conditions for the first time in this study.The debris flow slurry samples were from Jiangjiagou Ravine,Yunnan Province,China.The experimental results were found that at the low and middle stages of shearing,when the angular velocity ω<72.46 s-1,the loss modulus(G") was greater than the storage modulus(G’),i.e.G">G’.At the late stage of shearing,when the angular velocity ω≧72.46 s-1,the storage modulus was greater than or equal to the loss modulus,i.e.G’≧G",tanδ≦1(where phase-shift angleδ=G"/G’),and the debris flow slurry was in a gel state.Therefore,the progress of this experimental study further reveals the mechanism of hyperconcentrated debris flows with a high velocity on low-gradient ravines.     

一次带有雷电现象的冬季雪暴中尺度探测分析

对2009年11月9日北京市一次伴随雷电的局地暴雪过程的中小尺度特征进行了分析。采用了风廓线雷达资料、微波辐射计资料、自动气象站资料、多普勒天气雷达资料和卫星资料,对此次降雪的精细时空结构进行了分析,通过天气尺度及中小尺度分析,探讨了冬季对流产生的原因。结果表明:此次过程为华北回流天气过程,西南暖湿空气在低层冷空气之上产生高架对流和雷电天气,对流的触发机制是中空扰动。     

Regional-scale winter-spring temperature variability and chilling damage dynamics over the past two centuries in southeastern China

Winter-spring cold extreme is a kind of serious natural disaster for southeastern China. As such events are recorded in discrete documents, long and continuous records are required to understand their characteristics and driving forces. Here we report a regional-scale winter-spring (January–April) temperature reconstruction based on a tree-ring network of pine trees (Pinus massoniana) from five sampling sites over a large spatial scale (25–29°N, 111–115°E) in southeastern China. The regional tree-ring chronology explains 48.6% of the instrumental temperature variance during the period 1957–2008. The reconstruction shows six relatively warm intervals (i.e., ~1849–1855, ~1871–1888, ~1909–1920, ~1939–1944, ~1958–1968, 1997–2007) and five cold intervals (i.e., ~1860–1870, ~1893–1908, ~1925–1934, ~1945–1957, ~1982–1996) during 1849–2008. The last decade and the 1930s were the warmest and coldest decades, respectively, in the past 160 years. The composite analysis of 500-hPa geopotential height fields reveals that distinctly different circulation patterns occurred in the instrumental and pre-instrumental periods. The winter-spring cold extremes in southeastern China are associated with Ural-High ridge pattern for the instrumental period (1957–2008), whereas the cold extremes in pre-instrumental period (1871–1956) are associated with North circulation pattern.     

姚江-宁波平原中全新世海侵事件及古人类活动的快速响应

姚江-宁波平原是新石器河姆渡文化核心分布区,大量考古与古环境研究成果为深入探讨本地区7000年来的人地关系,尤其是新石器遗址文化间歇事件的原因创造了有利条件。本文通过对鱼山遗址地层记录的详细研究以及与区域多个遗址地层的空间对比,并对照该区自河姆渡文化一期以来古人类遗址的时空迁移过程,总结新石器文化演进中的海侵事件,并分析其与文化间歇的内在联系,初步认识如下:1)鱼山遗址从山麓到平原,地层记录存在明显差别,因此需要在不同的古地理位置获取剖面进行对比,才能重建更完整的古环境演变过程。2)鱼山遗址记录了2次海水入侵事件,分别发生于6300~6000cal.aB.P.和4500~3400cal.aB.P.,这两次事件与区内其他遗址文化层堆积中普遍叠压的自然淤积层或文化层缺失现象具有良好对应关系;研究区另有部分遗址在5400~5300cal.aB.P.也存在海水入侵迹象。3)新石器遗址时空分布呈现阶段性变化,河姆渡文化一、二期,遗址数量少,增幅小,主要分布于山麓缓坡地带,反映海水入侵造成研究区土地资源的局限性。河姆渡文化三、四期的遗址数量显著增加,且向开阔平原地带扩散,表明较稳定的海平面使研究区平原成陆面积增大,古人类对海岸带的利用快速扩张。良渚末期,遗址大幅度减少,直至商周才重新增多,反映持续的海水入侵制约古人类活动强度。上述遗址时空迁移特征反映海岸带古人类活动对环境变化的快速响应。     

北京平原区南部PGZ01孔第四纪地层划分及其环境意义*

对北京平原区南部大兴榆垡镇420m 深的PGZ01孔岩心进行了岩石地层、磁性地层、¹⁴C测年、介形类组合和孢粉组合研究。结果表明:(1)Matuyama(松山)/Gauss(高斯)和Brunhes(布容)/Matuyama(松山)极性界线分别位于280m和78.35m处,钻孔底部已经进入Gauss正极性带;取280m处Matuyama/Gauss极性界线作为第四系下限,显示可能的永定河泥石流-冲积扇在第四纪之前即到达了北京平原南部,但是华北平原上新统标志岩石地层单元--厚层棕红色黏土在Olduvai(奥尔都维)极性亚带之上即已出现。(2)结合AMS¹⁴C测年,尝试将约60m以上地层的氧化-还原状况,与对古季风影响反映灵敏的沿海平原钻孔同样深度地层进行对比,继而确定上更新统和全新统的底界深度分别位于56.60m和18.95m。(3)MIS5(海洋同位素阶段)以来的特征沉积物,与沿海平原钻孔地层有很好的可比性,同时也有8~4ka期间史前大洪水的影响。本研究为廊(坊)固(安)凹陷西北边缘区第四纪地层划分对比、古地理环境演化、活动断裂以及区域差异构造沉降研究,提供了重要的年代地层格架,对理解晚更新世以来古季风变化的环境效应有重要的启迪。     

Shipborne Over- and Under-Water Integrated Mobile Mapping System and Its Seamless Integration of Point Clouds

ABSTRACT

The rapid acquisition techniques of over- and under-water geoinformation is urgently needed. The Shipborne Over- and Under-water integrated Mobile Mapping System (SiOUMMS) applies plug-in and multi-process network technology to achieve integrated data acquisition and cooperative control of multi-sensors, such as Global Navigation Satellite System, Inertial Measurement Unit, laser scanner, and multi-beam echo sounder. The proposed system can meet the requirements of diverse application scenarios and sensors, allowing for flexibility and scalability. Meanwhile, coarse calibration based on a set of common points and fine calibration using the plane feature constraint are proposed for integratedly obtaining the exterior orientation elements of the laser scanner and the multi-beam echo sounder. Together, these methods provide theoretical support and technical help to the seamless integration of over- and under-water point clouds. Experiments are also described, proving that the root mean square error of over-water point clouds is 0.133 m, the average elevation clearance spacing between adjacent over- and under-water point clouds is less than 0.3 m, and the average horizontal clearance spacing is less than 0.2 m. At the same time, cases in this paper show that SiOUMMS has made important achievements in the integrated measurement of reefs, coastal zone, and inland waterways, and has broad prospects for future applications.     

Numerical simulation to quantify the leakage risk in a multi-layer aquifer system of pure brine recovery and CO<Subscript>2</Subscript>-enhanced brine recovery: a case study of potassium-rich brine recovery in Jianghan Basin of China

Deep brine recovery enhanced by supercritical CO₂ injection is proposed to be a win–win method for the enhancement of brine production and CO₂ storage capacity and security. However, the cross-flow through interlayers under different permeability conditions is not well investigated for a multi-layer aquifer system. In this work, a multi-layer aquifer system with different permeability conditions was built up to quantify the brine production yield and the leakage risk under both schemes of pure brine recovery and enhanced by supercritical CO₂. Numerical simulation results show that the permeability conditions of the interlayers have a significant effect on the brine production and the leakage risk as well as the regional pressure. Brine recovery enhanced by supercritical CO₂ injection can improve the brine production yield by a factor of 2–3.5 compared to the pure brine recovery. For the pure brine recovery, strong cross-flow through interlayers occurs due to the drastic and extensive pressure drop, even for the relative low permeability (k = 10^?20 m²) mudstone interlayers. Brine recovery enhanced by supercritical CO₂ can successfully manage the regional pressure and decrease the leakage risk, even for the relative high permeability (k = 10^?17 m²) mudstone interlayers. In addition, since the leakage of brine mainly occurs in the early stage of brine production, it is possible to minimize the leakage risk by gradually decreasing the brine production pressure at the early stage. Since the leakage of CO₂ occurs in the whole production period and is significantly influenced by the buoyancy force, it may be more effective by adopting horizontal wells and optimizing well placement to reduce the CO₂ leakage risk.     

科尔沁沙地草地植被对围封和放牧的响应

研究了科尔沁沙地疏林草地、针茅草原和草甸植被盖度、地上和地下生物量、物种多样性对围封和放牧的响应。结果表明：（1）围封与放牧草地的优势植物不同,围封草地植物群落优势植物为多年生禾本科植物,放牧草地中一年生植物和小半灌木优势明显。（2）围封和放牧草地的植物盖度、凋落物量、地上生物量和物种丰富度存在明显差异（P<0.05）;围封显著提高了植被盖度和地上生物量,由疏林草地、针茅草原到草甸,植物盖度和地上生物量逐渐增加,而3种草地植被凋落物量大小顺序为针茅草原> 疏林草地> 草甸;放牧条件下植物盖度、凋落物量和物种丰富度差异不显著（P>0.05）。（3）3种草地之间的地下生物量无显著差异（P>0.05）,但围封与放牧之间、不同土壤层次之间地下生物量存在明显差异（P<0.05）;围封显著提高草地的地下生物量（P<0.05）;草地地下生物量随着土壤深度表现出下降趋势（P<0.05）。长期放牧增加了草地一年生植物和小半灌木植物的优势,消除了不同草地之间植被盖度和物种丰富度的差异;而围封能提高草地多年生禾本科植物的优势、增加其物种丰富度,对于草地质量和植物多样性的恢复和保育具有积极作用。     

大亚湾表层沉积物中重金属分布特征

为了解大亚湾沉积物中重金属分布及污染状况,于2016年8月对大亚湾海域表层沉积物中重金属元素（As、Cd、Cr、Pb、Zn和Cu）展开调查,并将获得的各元素含量与粒度、Fe、Mn和总有机碳（TOC）等相关理化要素进行相关性分析。结果表明：大亚湾沉积物中重金属受陆源输入影响较大,含量基本呈现为沿岸高、湾内低的趋势,总体质量较好,基本符合第一类海洋沉积物质量标准要求;澳头湾和范和港附近海域人类活动密集,重金属含量较高。通过相关性分析结果发现,大亚湾重金属主要来源为岩石的风化和侵蚀、工业污水排放和渔业养殖等;Cu与铁锰氧化物结合性弱于其他元素,在还原性环境中被沉积物吸附形成金属Cu硫化物可能是喜洲岛附近海域Cu元素含量异常高值的原因;作为湾内有机质主要来源的水生浮游生物的生长状态对Cr、Zn和Pb含量影响较大;Cr、As和Pb与粉砂结合为主,Zn与粘土结合为主。