Examination of loose saturated sands impacted by a heavy tamper

This article examines the densification effects on the loose saturated sands impacted by a heavy steel tamper dropped from a great height (i.e., deep dynamic compaction, DDC). This examination was achieved by carrying out a series of piezocone penetration test (CPTu) soundings before and after the DDC impact. The depths at which densification took place ranged from 6.5 to 9.5 m below the ground surface (BGS) after one pass of DDC, and from 7.5 to 11.0 m BGS after two passes. The propagation of the surface waves generated in DDC disturbed the top 0.3–1.3 m soils. Directly below this disturbed layer, it was the most densified soil layer at the depths of 1.7–4.5 m BGS. The existence of the residual soft peat pockets reduced the densification effects substantially. Both the strength and the stiffness of the loose saturated sands were significantly improved after the DDC treatment. After two passes of impact, the liquefiable soils were densified to the level of unliquefiable along with dramatic reduction in liquefaction probabilities when subjected to earthquake motions.     

The assessment of water stress with the Water Poverty Index in the Shiyang River Basin in China

The paper is concerned with the application of the Water Poverty Index (WPI) as a holistic tool to assess the Shiyang River Basin’s water stress at the regional level. The basin is one of the inland river basins in China, with the degree of exploitation and utilization of water resources very high and water scarcity most severe. Appropriate indicators are needed to measure water stress for policy making and decision-making. The WPI links physical estimates of water availability with socio-economic factors associated with water scarcity. The study presents details of the methodology used, and the results show that the water stress in Minqin is the most severe in the basin, with a WPI value of 26.3, and that the water situation is the best in Jingchang with a WPI score of 66.9. In addition, measures in the basin are obtained of resources, access, capacity, use and environment.     

基于有理多项式系数模型的物方面元最小二乘匹配

针对物方面元最小二乘匹配仅适用于单中心投影框幅式成像的匹配制作区域DSM问题,提出基于有理多项式系数（RPC）模型的物方面元最小二乘匹配算法,结合匹配窗口区域内多中心平行投影方式,构建RPC模型下的投影方程,将物方面元最小二乘匹配算法从适用于单中心投影框幅式成像扩展到适用于多中心投影推扫式成像的立体匹配,并用SPOT5-HRG、GeoEye、IKONOS立体影像进行试验验证。试验表明,RPC模型能用于物方面元最小二乘匹配且不损失匹配精度,增加了物方面元最小二乘匹配的应用范围和价值。     

Nontectonic signals in reprocessed continuous GPS position time series of CMONOC

The nearly nine-year continuous GPS data collected since 1 March 1999 from the Crustal Motion Observation Network of China(CMONOC) were consistently analyzed.Most of the nonlinear movements in the cumulative position time series pro-duced by CMONOC data center disappeared;and more accurate vertical terms and tectonic signals were extracted.Displacements caused by atmospheric pressure loading,nontidal ocean loading,soil moisture mass loading,and snow cover mass loading using the National Centers for Environmental Prediction(NCEP) Reanalysis I/II models and Estimation of the Circulation and Climate of the Ocean(ECCO) data can explain most of the vertical annual terms at many stations,while only parts can be explained at Lhasa and southern coastal sites,indicating that there are some deformation mechanisms that are still unknown or not modeled accurately.The remarkable differences in vertical position time series for short-baseline sites reveal that GPS stations can be greatly affected by lo-cal factors;and attention should be paid when explaining observed GPS velocity vectors.     

Sensitivity of Typhoon Vamei (2001) Simulation to Planetary Boundary Layer Parameterization Using PSU/NCAR MM5

This paper investigates the sensitivity of the numerical simulations of a near equatorial Typhoon Vamei (2001) to various planetary boundary layer (PBL) parameterization schemes in the Pennsylvania State University (PSU)/National Centre for Atmospheric Research (NCAR) non-hydrostatic mesoscale model (MM5). The numerical simulations are conducted on two domains at 45 and 15 km grids nested in a one-way fashion. Four different PBL parameterization schemes including the Blackadar (BLK) scheme, the Burk–Thompson (BURKT) scheme, the NCEP Eta model scheme and the NCEP medium range forecast (MRF) model scheme are investigated. Results indicate that the intensity and propagation track of the simulated near equatorial typhoon system is not very sensitive to the different PBL treatments. The simulated minimum central pressures and the maximum surface wind speeds differ by only 5–6 hPa and 6–8 ms⁻¹, respectively. Larger variations between the simulations occur during the weakening phase of the typhoon system. While all schemes simulated the typhoon with reasonable accuracy, the ETA scheme produces the strongest storm intensity with the largest heat exchanges over the marine environment and the highest warm moisture air content in the PBL around the core of the storm.     

庐枞矿集区大地电磁探测及电性结构初探

在庐枞矿集区开展大地电磁测深(Magnetotelluric,MT)工作,有助于研究庐枞矿集区区域地质结构、构造,同时,对强干扰地区大地电磁下扰信号规律的研究和MT数据的处理与解释水平的提高有着重要的理论意义.论文首先阐述了庐枞盆地的地质概况及深部MT探测的研究现状,接着介绍了庐枞矿集区大地电磁测深数据采集及相关实验研...     

Trace element and REE geochemistry of fine- and coarse-grained sands in the Ordos deserts and links with sediments in surrounding areas

In addition to mineral analyses, REE and trace element geochemical characteristics of fine- and coarse-grained sands in the Ordos deserts and other sediments in surrounding areas are investigated.Commonly the samples consist of quartz, feldspar and muscovite and less clinochlore, dolomite and ankerite. In few samples muscovite is absent.REE and trace compositions are spatially uniform for the same grain-size sands, suggesting that they could have the same sources or/and were well homogenized. However, fine- and coarse-grained sands in the Ordos deserts show different REE and trace element compositions. Fine-grained sands show higher contents of REE and trace elements than those of coarse-grained sands. They differ in Eu anomalies and (La/Yb)_N ratios although both fractions are characterized by the steep LREE and smooth HREE patterns. The fine- and coarse-grained sands are also distinct in some characteristic element ratios (e.g., Th/Co, La/Sc, Th/Sc and Y/Ni).REE and trace element patterns of the two different grain-size fractions are closely associated with geological properties of individual sources rather than the mineralogical differentiation induced by wind sorting. The coarse-grained sands mainly resulted from sandstone weathering in the Ordos deserts and movements of coarse particles by wind. REE and trace element patterns of fine-grained sands in the Ordos deserts differ from those of sandstones in the Ordos deserts, the alluvial sands in the surrounding mountains and the coarse fluvial sands in the Yellow River. They resemble the fine fluvial sands in the Yellow River. In addition, arid areas of Northwest China such as the Tarim Basin and the Alxa Plateau should not be ruled out as the source of the fine-grained sands in the Ordos deserts because these arid areas reserve plenty of fine-grained sediments and also located in the upwind directions of the Ordos deserts.     

前兆波及其地震预测意义

通过回顾自20世纪60年代以来地震前兆波的研究与地震预测实践的进展情况,分析利用地震前兆波进行地震预测研究所取得的一些有意义的进展及其在科学上面临的困难,分别对前兆波及其定义、前兆波预测大地震事件基本依据、前兆波观测技术概述、前兆波的地震预测意义进行了探讨.文中定义了地震前兆波,以固体均匀弹性中的介质点波动方程和大量震例总结的前兆波阶段性特征,说明利用地震前兆波预测大地震事件具有坚实的理论基础和实践依据.文中阐述了前兆波观测技术的发展要求,并提出了改变目前的被动观测状况、对观测目标区域发生破坏性地震的短期和临震前兆进行主动观测的科学思路;应强化对地震震源区的观测,利用前兆波携带的信息研究震源及其附近地区的介质参数变化,对实现短临地震预测是有意义的.     

吉林省敦化市乡村人群气候变化感知的偏差及群体分异研究

通过问卷调查,具体分析了吉林省敦化市乡村人群对气候变化趋势和极端冷暖年的感知偏差及人群分异.发现乡村人群对气候变化趋势的感知与科学事实比较符合,由于对变暖转折年代更敏感,因而对变暖的确认度在一些时段与科学事实在变化程度或幅度上存在比较大的偏差.乡村人群对极端冷暖年不如对趋势感知的准确度高.经验积累影响乡村人群对气候变化...     

电感耦合等离子体发射光谱法和火焰原子吸收光谱法连续测定化探样品中12个元素

建立了地质化探样品中不同含量和检出限要求的12个元素的连续测定方法。样品经一次取样,用盐酸-氢氟酸-硝酸-高氯酸溶样,电感耦合等离子体发射光谱法测定铜、铅、锌、钴、镍、镉、锶、钡、钒、锰后,加碘化钾-甲基异丁基甲酮萃取分离,火焰原子吸收光谱法测定银、镉。银、镉的相对标准偏差(RSD,n=12)分别为6.5%、4.7%。与现行分析方法相比,建立的方法灵敏度和精密度高、准确度好,降低了生产成本,缩短了检测时间,尤其适合大量化探样品的测定。