Groundwater interaction assessment based on the large-scale mapping of geological and hydrogeological conditions in Moscow

Assessing the interaction between aquifers is crucial for estimating the extent of protection of the aquifer in Carboniferous limestone (which is the main source of potable water supply to Moscow area) against contaminants penetrating from the overlying aquifers. The presented approach to assessing groundwater interaction and protection is based on large-scale mapping of the geological and hydrogeological conditions in Moscow. The obtained results may be used for solving the problem of groundwater protection against contamination, as well as for planning the engineering activities in the city.     

A map of large-scale (detail) engineering geological zoning of Moscow territory

The results of a large-scale engineering geological zoning of Moscow territory are given. The work was carried out according to the order of the Moscow Government “On the Compilation of Thematic Geological Large-Scale Maps of Moscow Territory.” The map of engineering geological zoning is based on the integration of data on the structural-geodynamic, geomorphologic, and geological structure, hydrogeological conditions, and the occurrence of hazardous natural and human-induced processes and phenomena. The basic principle of map compilation was the successive typological division of the territory into four taxonomic levels with the use of an index method of denotation of taxa with different ranks.     

Identification of karst features in a zone of active water exchange in a river valleywith disturbed hydrogeological conditions

The main features of water-bearing rocks and the interaction in the water-rock system, as well as tendencies in the transformations of the regime of liquid, mineral, and gas phases in Moscow River valley, are identified based on a detailed study of hydrogeological and engineering-geological conditions. Recommendations regarding the procedure of studying karst in complex hydrogeological conditions were formulated.     

Assessment of hydrogeological conditions in basement aquifers of the Precambrian Oban massif, southeastern Nigeria

A combined analysis of lineament length density from radar imagery and surface resistivity data is used to assess the hydrogeological conditions in the Oban massif, Nigeria. The results show that the data guided the qualitative and quantitative estimation of some aquifer parameters. These include resistivity of the water bearing formations (280–740 ω m), thickness (5–140 m), limited hydraulic conductivity (8.53-13.18 m/day) and transmissivity (410.65–725.88 m²/day) data. In addition, the lineament length density for the area ranged between less than 0.2 to slightly more than 0.4. Site evaluation for the location of productive boreholes/wells using a groundwater potential index (GWPI) indicates that areas with a GWPI of greater than 35 are consistent with relatively high yield.     

海上丝绸之路大型地质灾害:特点与现状

海上丝绸之路深海地质灾害类型众多.主要分析了海底滑坡、三浅地质灾害和地震海啸这三种类型的地质灾害.传统多波束测深、三维地震勘探、深海钻探、声呐成像系统、海底地理信息系统是识别海底滑坡最有效手段.然而,准确解释和量化滑坡参数对于确定滑坡群的机制需要物理实验模拟和数值模拟;对于"三浅"地质灾害,地球物理技术是最有效的钻前预测方法,但在超压的定量预测方面还存在一些不足,识别准确度不高,因而,需要发展海底原位监测技术,提高"三浅"地质灾害的预测精度.南海海啸最主要的威胁来自其东部边缘的马尼拉俯冲带,而非印度洋.我国国家海洋环境预报中心已开发应对南海及其附近区域的潜在海啸威胁的定量海啸预警系统.但是,海上丝绸之路环俯冲带产生的地震海啸,影响甚广,亟待建立完善的预警系统.     

大地水准面高对InSAR大范围地壳形变监测的影响分析

由于InSAR数据处理所用的WGS84参考椭球系统与通用的DEM高程系统(EGM96大地水准参考面)不一致,在InSAR形变监测分析中会引入大地水准面高导致的误差.本文利用覆盖青藏高原北部阿尔金断裂带西段的27景Envisat ASAR宽幅模式数据和44景条带模式数据,研究了大地水准面高与InSAR大范围形变测量不确定性的关系:(1)模拟分析表明对于100 m的垂直基线,8.8 m的DEM测量误差,若研究区域存在20 m的大地水准面高的变化,对宽幅或条带模式InSAR形变测量造成的影响将由3 mm增至10 mm左右;(2)实例验证表明对于不同的研究区域,大地水准面高与该地区地形变化存在较大相关性,对于同一研究区域,垂直基线的大小决定了大地水准面高对InSAR不确定性的影响程度;(3)对于大地水准面高有较大梯度变化的研究区域,组合短基线方法与去除轨道平面的方法难以消除大地水准面高的影响.使用基于WGS84高程系统的DEM,可以为InSAR形变测量分析提供统一的高程基准,有效避免大地水准面高误差的影响.     

Effects of canyon topography and geological conditions on strong ground motion

The finite and infinite element coupling system is used to study the effects of canyon topography and geological conditions on strong ground motion. The system is first applied to a semi-cylindrical shaped canyon using SH wave propagation to verify its accuracy. It is concluded that different topography conditions may have important effects on the ground motions along the canyon. The geological conditions, by which we mean different softening of weathered strata of the canyon surface, will have significantly amplified effects on the free field motions. This fact suggests that a deep weathered rock excavation of arch dam abutments for stability purposes will also benefit earthquake resistance of the dam due to the reduction of ground motions of the sound rock.     

寿山石的成矿地质条件和矿物组成

长期研究表明,寿山石的成矿地质条件主要受地层、构造、火山机构和火山成矿等综合作用控制。寿山石的矿物成分主要为地开石、高岭石和叶蜡石。因寿山石的成矿地质条件、矿物组成和产出部位的不同,形成色彩绚丽、命名异样、品种繁多、分类殊异。但通常以其成因、产状和历史传统分为田坑石、山坑石和水坑石三类。为便于识别、研究和讨论,将寿山石的主要品种及其特征一并简介。     

Engineering geological conditions and protection of Olympic park territory in Sochi

The climatic, engineering geological, and environmental conditions in Imeretinskaya depression are described in the context of the implementation of construction program for Winter Olympic Games 2014, including a large set of structures to be constructed in this area: Olympic park, Olympic village, engineering and transport facilities.     

Identification of the four rearranged hopane series in geological bodies and their geochemical significances

Saturated fractions in a total of 23 oil samples and hydrocarbon source rocks from the Songliao, Tarim,and Ordos Basins have been analyzed by GC–MS and GC–MS–MS. According to the relative retention, mass spectral characteristics, and comparison with existing literature, a complete carbon number distribution ranging from C27 to C35(without C28) in the 17a(H)-diahopane series and early-eluting rearranged hopane series is identified. Compounds in the 18a(H)-neohopane series(Ts and C29Ts) and21-methyl-28-nor-hopane series(29Nsp and 30Nsp) are also noted. These four series of rearranged hopanes seem to occur in both brackish-saline lacustrine and coal measure environments. However, the coal measure and swamp environments being under an oxic condition, compared with brackish-saline lacustrines, are presumably more helpful to the formation of 30 E. Diversity in the content and distribution patterns indicate that rearranged hopanes could serve as good indicators of organic facies, depositional environment and maturity in petroleum geology.     

Pyrgos earthquake damages (based on E.M.S.-1992) in relation with geological and geotechnical conditions

On 26 March 1993 seismic activity at Ilia, West Peloponnesse, Greece resumed to extensive damages. The more severe destruction, with significant differentiation from one locality to another, was observed at the city of Pyrgos. To get a clear picture of the distribution of intensities, recording of damages was conducted according to the E.M.S.-1992. Application of this method at the wider area of Pyrgos showed that the highest intensity was VIII and the minimum was V. Detailed geological mapping and geotechnical investigation at the city of Pyrgos was also conducted and revealed a number of geological formations with special lithological and geotechnical characteristics. Faults that follow an E-W general direction dominate at the area and are part of the same fault zone that gave the earthquakes. Synthesis of the available data showed that there is a clear correlation between the intensities observed and the geological, tectonic and geotechnical conditions.     

Determining the permeability of fractured rocks based on joint mapping

A typical fractured rock mass is intersected by several sets of discontinuities, which provide the main flowpath for ground water. Due to the limitations of data obtained by conventional field measurements, it is often difficult to estimate the anisotropic permeability tensor associated with the joints existing in the rock mass. For that reason, determining permeability tensors for fractured rocks is an important topic in rock mass hydraulics. Based on field surveys, joint parameters can be analyzed by using probabilistic and statistical tools, and three-dimensional mapping of the jointed rock mass. Through analysis of a single joint's hydraulic characteristics, the principal value of the permeability tensor for the jointed rock mass can be determined by using Monte Carlo methods and the searching percolation trace method, which is developed in this paper. The study reports on practical examples demonstrating that results from the methods discussed in this paper are in agreement with those from field hydrogeological surveys and measurements.     

基于重磁场多尺度边缘检测的地质构造信息识别与提取——以铜陵矿集区为例

重磁场是地下地质体密度、磁性分别响应的综合,蕴涵着丰富的地质构造信息,如何将其有效地提取出来是正确认识地下结构的关键环节.本文在总结重磁场构造信息提取研究进展的基础上,将构造信息提取突破口归结为重磁场的边缘增强与检测.通过构建理论模型,对常用的边缘检测方法开展了对比试验,并以长江中下游成矿带中的铜陵矿集区为例,开展了实际资料的处理和研究.获得以下认识和结论:(1)多尺度边缘检测方法较其他方法更能准确提取模型边界,更适合于构造信息识别与提取;(2)在铜陵矿集区识别出18条断裂构造,确定了铜陵隆起的边界,断裂构造的走向主要为北东向,前人所谓"棋盘格式"断裂构造系统并不存在;(3)圈定了岩体的分布范围,在铜陵矿集区北缘,发现了2处隐伏岩体;(4)施家冲、戴家汇岩体周边是寻找矽卡岩型、斑岩型铜金矿的有利地段,铜陵隆起和繁昌火山岩盆地分界断裂两侧是寻找热液型铅锌矿和金矿的重要靶区.     

基于MAPGIS的福建省矿山地质环境综合评价分析

福建省矿业开发产生的环境地质问题主要有占用破坏土地、破坏地貌景观、水土流失、水土污染、水均衡破坏以及采空塌陷、岩溶塌陷、崩滑流矿山地质灾害等。矿山地质环境综合评价单元的划分采用正方形网格单元。选取矿山地质环境现状、地质环境条件、矿产资源开发利用规划、矿山生态环境恢复治理难易程度等作为评价因子。根据各因子对矿山地质环境质量影响存在重大差异及可分层次的实际情况,采用质量指数评价模型作为矿山地质环境综合评价模型。利用MAPGIS的空间分析功能,对整个系统进行综合评价。然后根据综合指数的大小,将全省圈定出28个区的矿山地质环境综合质量划分为严重区、较严重区和一般区。     

An assessment of large-scale flood modelling based on LiDAR data

Large-scale flood modelling approaches designed for regional to continental scales usually rely on relatively simple assumptions to represent the potentially highly complex river bathymetry at the watershed scale based on digital elevation models (DEMs) with a resolution in the range of 25–30 m. Here, high-resolution (1 m) LiDAR DEMs are employed to present a novel large-scale methodology using a more realistic estimation of bathymetry based on hydrogeomorphological GIS tools to extract water surface slope. The large-scale 1D/2D flood model LISFLOOD-FP is applied to validate the simulated flood levels using detailed water level data in four different watersheds in Quebec (Canada), including continuous profiles over extensive distances measured with the HydroBall technology. A GIS-automated procedure allows to obtain the average width required to run LISFLOOD-FP. The GIS-automated procedure to estimate bathymetry from LiDAR water surface data uses a hydraulic inverse problem based on discharge at the time of acquisition of LiDAR data. A tiling approach, allowing several small independent hydraulic simulations to cover an entire watershed, greatly improves processing time to simulate large watersheds with a 10-m resampled LiDAR DEM. Results show significant improvements to large-scale flood modelling at the watershed scale with standard deviation in the range of 0.30 m and an average fit of around 90%. The main advantage of the proposed approach is to avoid the need to collect expensive bathymetry data to efficiently and accurately simulate flood levels over extensive areas.     

Effects of hydrogeological and climate change on the subsurface thermal regime in the Sendai Plain

We estimated the effects of hydrogeological and surface temperature warming on subsurface thermal regime from the temperature-depth profiles and hydrological data of groundwater quality both in the quaternary and tertiary systems in the Sendai Plain as a preliminary step toward reconstruction of climate changes.Annual mean air temperature in the plain has increased about 1.5 °C in the last 70 years and this surface warming resulted in low or negative thermal gradient. However, anomaly of thermal gradient was recognized in not all temperature-depth profiles. Groundwater chemical compositions and stable isotope data (δD and δ¹⁸O) show that the groundwater flow system has marked difference between those of tertiary and quaternary systems. Calculated results of three dimensional groundwater flow and heat transport model ensure the above hypothesis and shows that thermal gradient changes at close to basement of the quaternary system. The differences in groundwater flow systems are expressed as subsurface thermal gradient anomalies in the temperature-depth profiles in the Sendai Plain. Furthermore, one-dimensional numerical analyze including the effect of surface warming indicates that calculated profile has departure from steady state line at depths in 60-80 m agree well with observed one.     

On the subsoil radon and neutron flux variations in the conditions of the Moscow syneclise on the eve of the earthquake in the Sea of Okhotsk on May 24, 2013

By monitoring the variations in the subsoil radon concentration in one of the geodynamically active zones of the Moscow syneclise, the effects are detected of changes in the stress-strain state of the Earth’s crust which predetermined the development of the processes that caused the deep-focus earthquake in the Sea of Okhotsk on May 24, 2013. The joint analysis of subsoil radon variations and neutrino flow variations measured in the same structural–geodynamical conditions support the previous data on the global character of the processes contributing to the preparation of strong and catastrophic earthquakes.     

不同地质条件下反演低频模型构建方法分析

地震波阻抗反演是油气勘探开发过程中基于地震数据刻画地下储层特征及分布范围的重要工具,但受地震采集条件限制,地震数据往往是带限的,缺乏低频成分.低频成分蕴含地质构造的基本信息,缺失低频成分在一定程度上会降低基于反演数据开展储层预测的精度.因此,如何构建低频模型补偿地震低频成分就成为地震波阻抗反演的关键.首先,以均匀介质背...