A multivariate sedimentary environmental analysis of Great South Bay and South Oyster Bay, New York

A multivariate statistical strategy for classifying paleoenvironments is effective for studying modern sedimentary processes in western Great South Bay and South Oyster Bay, New York. The 13 whole phi weight percent variables were tested for redundancy with R-mode cluster analysis. The samples were partitioned statistically into five environmentally significant facies using Q-mode cluster analysis: (A)sandy gravel, (B)sandy silt, (C)silty sand, (D)slightly gravelly sand, and (E)fine sand. An ordination depicted gradational relationships among the samples and the facies. It was used to evaluate the environmental and textural parameter gradients within the sample space. Interpretations obtained in this manner and by examination of the grain-size curves suggest that these sediments were deposited by waves and currents on beaches and in wave zones (facies C and E),shoal areas (facies B),and tidal channels (facies A and D).Tidal currents, wave action, and eelgrass control the distribution of sediments within the two bays.     

Leaf physiognomy and climate: A multivariate analysis

Research has demonstrated that leaf physiognomy is representative of the local or microclimate conditions under which plants grow. The physiognomy of leaf samples from Oregon, Michigan, Missouri, Tennessee, and the Panama Canal Zone has been related to the microclimate using Walter diagrams and Thornthwaite water-budget data. A technique to aid paleoclimatologists in identifying the nature of the microclimate from leaf physiognomy utilizes statistical procedures to classify leaf samples into one of six microclimate regimes based on leaf physiognomy information available from fossilized samples.     

基于三种多变量不安定指数分析模型的汶川县地质灾害易发性评价

采用多变量不安定指数分析法模型并加以改进,应用于汶川县地质灾害易发性评价。选取坡度、坡向、地层岩性、距断层距离、植被覆盖率及距水系距离六项影响因子,结合四川省自然资源厅发布的汶川县地质灾害隐患点数据,以幂次相乘、线性累加、幂次累加这三种不同的不安定指数分析法模型分别得到了研究区地质灾害易发性分区图,并用接受者操作特性曲线（Receiver Operating Characteristic curve, ROC curve）验证了各种模型的评价性能。结果表明:（1）对本案例而言,幂次相乘模型相较其它两种模型具有最高的精度;（2）汶川县地质灾害“极高”“高”“中”“低”“极低”易发区的面积占比分别为:19.3%、24.6%、19.2%、19.3%、17.6%,且研究区地质灾害易发性较高的区域多分布在断裂带附近。本研究成果可为区域地质灾害防治工作提供理论借鉴和技术参考。     

Gis-aided land evaluation and decision-making for regulating urban expansion: A South African case study

A computerised aid to the land use planning process is demonstrated on the urban edge of Cape Town, South Africa. Multi-criteria analysis is performed in the IDRISI GIS package to evaluate development suitability for four land use categories according to appropriately measured and weighted criteria. The four suitability images are then subjected to multi-objective land allocation to demarcate optimum locations for each land use type. The decision-making process entails execution of seven consecutive steps which are discussed in detail and applied in the case study. Technical decisions are rationalised and results displayed. The paper concludes with a call for the development of applications which can incorporate public participation in this type of decision-making process to ensure the wider acceptance of advanced GIS technology as appropriate technology.     

Factors influencing cost-effectiveness of maintenance of power distribution poles subjected to hurricanes: a system-dynamics-based analysis

Based on a system dynamics (SD) model of long-term cost-effectiveness of power pole maintenance over 50 years, the influence of factors that affect cost-effectiveness was examined. Taking a typical region subjected to hurricanes (i.e., Miami-Dade County, USA) as a case, the SD model was established and tested with scenarios of power poles maintenance strategies. Factors such as wind speed variation (due to climate change), regional annual growth rate of the pole population, and discount rate were explored. It was shown that changing the parameters for these factors results in the following: The variation of wind speed due to climate change produces a negative impact on cost-effectiveness under the given replacement strategy; the factors of wind speed and annual growth rate of poles have a significant influence on the replacement ratio of poles particularly in the later period such as later 30 years; similarly, the discount rate has a marked impact on cumulative cost in the later decades. The difference between the contribution of factors is more significant in the later stages of the design life. The simulation results indicate how the change of these factors can lead to an impact on cost-effectiveness over time. The results have meaningful strategy implications, allowing an optimization of the timing of maintenance and a focus on different critical factors at various time periods.     

Urban networks, community organising and race: an analysis of racial integration in a desegregated South African neighbourhood

The paper addresses the question of racial integration in Delft South, a desegregated low-income neighbourhood in Cape Town developed through the provision of state funded housing to families previously classified coloured and African. Through a qualitative analysis, the research examines the effect relocation has had on the racial character of economic and social networks around which resident families construct their everyday activities. In light of the importance of race in shaping these networks, the paper then examines the relationship between access to housing and practices of social and spatial integration, in particular organisation of and participation in street- and neighbourhood-level organisations. I demonstrate that in Delft South legacies of segregation persist in residents’ reliance on economic and social networks built on long, durable histories and geographies of racial segregation. Although physical relocation has not led to a lessening of the importance of racial identities, other identities built around issues such as neighbourhood norms, housing politics, and issues of criminality and legality manifest according to circumstances and residents’ interests. Context and situation therefore are significant for whether and to what degree race and place matter in the post-apartheid context.     

Compositional multivariate statistical analysis of thermal groundwater provenance: A hydrogeochemical case study from Ireland

Thermal groundwater is currently being exploited for district-scale heating in many locations world-wide. The chemical compositions of these thermal waters reflect the provenance and circulation patterns of the groundwater, which are controlled by recharge, rock type and geological structure. Exploring the provenance of these waters using multivariate statistical analysis (MSA) techniques increases our understanding of the hydrothermal circulation systems, and provides a reliable tool for assessing these resources.Hydrochemical data from thermal springs situated in the Carboniferous Dublin Basin in east-central Ireland were explored using MSA, including hierarchical cluster analysis (HCA) and principal component analysis (PCA), to investigate the source aquifers of the thermal groundwaters. To take into account the compositional nature of the hydrochemical data, compositional data analysis (CoDa) techniques were used to process the data prior to the MSA.The results of the MSA were examined alongside detailed time-lapse temperature measurements from several of the springs, and indicate the influence of three important hydrogeological processes on the hydrochemistry of the thermal waters: 1) salinity and increased water-rock interaction; 2) dissolution of carbonates; and 3) dissolution of sulfides, sulfates and oxides associated with mineral deposits. The use of MSA within the CoDa framework identified subtle temporal variations in the hydrochemistry of the thermal springs, which could not be identified with more traditional graphing methods, or with a standard statistical approach. The MSA was successful in distinguishing different geological settings and different annual behaviours within the group of springs. This study demonstrates the usefulness of the application of MSA within the CoDa framework in order to better understand the underlying controlling processes governing the hydrochemistry of a group of thermal springs in a low-enthalpy setting.     

The impact of residential desegregation on social integration: Evidence from a South African neighbourhood

This paper analyses the potential for social integration in post-apartheid urban South Africa by examining the lives of those already living in desegregated spaces. The case study is a low-cost state-assisted housing project situated in the wealthy southern suburbs of Cape Town. In this social housing project, named Westlake village, coloured and Black African (alongside a handful of white and Indian) residents were awarded state housing in 1999 as replacement for their previous homes (informal and formal), which were demolished to make way for a mixed land-use development, of which their new homes form a small component. Westlake’s desegregation is found to extend beyond mere residential abode, affecting resident’s everyday lives to the extent that apartheid’s history and geography are superseded by other factors (such as proximity and affordability) in decision-making. Furthermore, integration at the everyday level of informal neighbourly mixing is prevalent. Although more formal cross-race friendships are rare, discussion reveals this as a consequence of Westlake’s specific socio-historic identity rather than racial divisions per se. Empirical evidence is used to propose a continuum of social integration experience. This continuum addresses the form of integration, for example greeting in the street, visiting homes, inter-marriage; and also the spaces of integration, for example physical space (shared neighbourhood), economic space (common employment-type), social space (cross-race friendship), political space (common involvement in civic organisations) and cultural space (shared sense of belonging).     

Hill slope stability analysis using two and three dimensions analysis: A comparative study

Slope instability is very common phenomenon, especially in tectonically active hills of the lesser Himalaya. The deformed, weathered and fragile rocks of the lesser Himalaya are often vulnerable under natural or anthropogenic influences. There were several cases of slope failure along highway sections in Uttarakhand Himalaya. The study was carried out along a highway section of NH-109. The factor of safety (FoS) is commonly most acceptable parameter that analyses the health of slopes. The two dimensional (2D) numerical analysis techniques are commonly used to obtain the FoS. It is observed that many times FoS obtained from 2D analysis techniques do not qualify the actual conditions and are usually lower in value as compared to ground conditions. This, in turn, increases the cost of remedial measures used for protection of slopes. This paper presents a comparative study of 2D and 3D numerical analysis based on the finite difference method (FDM) using fast Langrangian analysis of continua (FLAC) codes. The study indicates that there is no appreciable difference between FoS values obtained from 2D and 3D analysis based on the selected slope conditions. The difference ranges from 0.02 to 0.07 for analysed cases in uniform rock mass. The study also exhibits some of the important analytical observations and effects of variables on resultant FoS.     

基于多元回归分析的煤储层高渗区预测——以沁水盆地为例

煤储层的渗透性是控制煤层气开采的主要储层参数之一。本文以沁水盆地为例,在总结我国煤储层渗透性特征的基础上,依据煤储层渗透性的影响因素,用多元回归分析方法建立煤储层渗透性预测模型。沁水盆地煤储层渗透性的多元回归方程,具有较高的拟合度。预测结果显示,沁水盆地有利于煤层气开发的高渗区,主要集中在南部的潘庄-阳城、北部的阳泉-寿阳及太原西山煤田等地区。     

Study on polycyclic aromatic hydrocarbons（PAHs） contents and sources in the surface so~l or l-lmznou City, South China, based on multivariate statistics analysis

Studies of polycyclic aromatic hydrocarbons (PAHs) in the surface soil were conducted in Huizhou City, which is located in the Pearl River Delta, South China. Sixteen PAHs in 42 soil samples were detected. The results showed that 4 components of PAHs were detectable in all soil samples, and other 12 components were also detectable to some extent. The total PAHs contents range from 35.40 to 534.5 μg/kg with the mean value of 123.09 μg/kg. Soil in Huizhou was slightly polluted by PAHs according to Maliszewska-Kordybach’s study. It can be confirmed that the increase of PAHs contents in the surface soil of Huizhou City is closely connected to human activities. Multivariate analysis was also made in this study. Principal component analysis was used to constrain their origins, and 3 principal components (PCs) were extracted. The results showed that coal combustion and oil spilling made the major contributions to PAHs. Cluster analysis was made and 16 priority PAHs were classified as 4 sorts, and the result revealed the differences in environmental behavior, chemical properties and sources of PAHs.     

Investigation by multivariate analysis of groundwater composition in a multilayer aquifer system from North Africa: A multi-tracer approach

A multi-tracer approach has been carried out in the Sbeïtla multilayer aquifer system, central Tunisia, to investigate the geochemical evolution, the origin of groundwaters and their circulation patterns. It involves statistical data analysis coupled with the definition of the hydrochemical and isotopic features of the different groundwaters. Principal Components Analysis (PCA) of geochemical data used in conjunction with bivariate diagrams of major and trace elements indicate that groundwater mineralization is mainly controlled by water-rock interaction and anthropogenic processes in relation to return flow of irrigation waters. The PCA of isotopic data and bivariate conventional diagrams of stable and radiogenic isotopes i.e. δ¹⁸O vs. δ²H and δ¹⁸O vs. ¹⁴C provide valuable information about the origin and the circulation patterns of the different groundwater groups. They permit classifying groundwaters into three groups. The first group is characterized by low ³H concentrations, low ¹⁴C activities and depleted stable isotope contents. It corresponds to an old end-member in relation with palaeoclimatic recharge which occurred during the Late Pleistocene and the Early Holocene humid periods. The second group is distinguished by high to moderate ³H concentrations, high ¹⁴C activities and enriched heavy isotope signatures. It corresponds to a modern end-member originating from a mixture of post-nuclear and present-day recharge in relation to return flow of irrigation waters. The third group is characterized by an average composition of stable and radiogenic isotope signatures. It provides evidence for the mixing between the upward moving palaeoclimatic end-member and the downward moving present-day end-member.     

基于多变量统计分析和水化学特征的海水入侵特征研究——以青岛市崂山区为例

沿海地区地下水环境问题日益突出,进行地下水水化学特征及演化规律的研究,能够更有效地开展地下水环境的监测和保护。以青岛市崂山区地下水为研究对象,综合运用统计分析、主成分分析、Piper图解法、HFE-D图解法、Chadha’s矩形图法等方法,对研究区海水入侵特征与地下水化学特征演化进行分析,探究地下水水化学特征及演化规律,并进一步评价了海水入侵现状。结果表明,研究区地下水以Na+、Ca2+、Cl−、${\rm{SO}}_4^{2-}$为主要优势离子,地下水化学类型多为Cl·SO4-Na型和SO4·Cl-Ca·Mg型。地下水中Cl−浓度变化幅度较大,且其均值超出了有无海水入侵的分界值（250 mg·L−1）,地下水可能发生一定程度的海水入侵;青岛市崂山区地下水呈中性至弱碱性（pH均值=7.0~8.0）,是沿海地区长期的水文地球化学过程的影响;地下水化学变化主要受自然因素（岩石与水的相互作用）或人为因素（农业和家庭活动）的控制;采用反距离加权（IDW）方法,结合地理信息系统（GIS）,进行海水入侵位置的空间映射,研究结果表明崂山区海水入侵主要分布于江家土寨东−浦里社区北入侵段,王哥庄−港西−港东入侵段、仰口湾入侵段、登瀛村−栲栳岛入侵段。     

Controlling Factors of Organic Nanopore Development: A Case Study on Marine Shale in the Middle and Upper Yangtze Region,South China

The Upper Ordovician Wufeng-Lower Silurian Longmaxi and the Lower Cambrian Qiongzhusi shales are the major targets for shale gas exploration and development in China. Although the two organic-rich shales share similar distribution ranges and thicknesses, they exhibit substantially different exploration and development results. This work analyzed the nanopore structures of the shale reservoirs in this region. Pore development of 51 shale samples collected from various formations and locations was compared using the petromineralogical, geochemical, structural geological and reservoir geological methods. The results indicate that the reservoir space in these shales is dominated by organic pores and the total pore volume of micropores, mesopores, macropores in different tectonic areas and formations show different trends with the increase of TOC. It is suggested that organic pores of shale can be well preserved in areas with simple structure and suitable preservation conditions, and the shale with smaller maximum ancient burial depth and later hydrocarbon-generation-end-time is also more conducive to pore preservation. Organic pore evolution models are established, and they are as follows: ① Organic matter pore development stage, ② Early stage of organic matter pore destruction, and ③ late stage of organic matter pore destruction. The areas conducive to pore development are favorable for shale gas development. Research results can effectively guide the optimization and evaluation of favorable areas of shale gas.     

Prediction of source rock characteristics based on terpane biomarkers in crude oils: A multivariate statistical approach

The distributions of eight tricyclic and eight pentacyclic terpanes were determined for 216 crude oils located worldwide with subsequent simultaneous RQ-mode factor analysis and stepwise discriminate analysis for the purpose of predicting source rock features or depositional environments. Five categories of source rocks are evident: nearshore marine (i.e., paralic/deltaic); deeper-water marine; lacustrine; phosphaticrich source beds; and Ordovician age source rocks. The first two factors of the RQ-mode factor analysis describe 45 percent of the variation in the data set; the tricyclic terpanes appear to be twice as significant as pentacyclic terpanes in determining the variation among samples. Lacustrine oils are characterized by greater relative abundances of C₂₁ diterpane and gammacerane; nearshore marine sources by C₁₉ and C₂₀ diterpanes and oleanane; deeper-water marine facies by C₂₄ and C₂₅ tricyclic and C₃₁ plus C₃₂ extended hopanes; and Ordovician age oils by C₂₇ and C₂₉ pentacyclic terpanes. Although thermal maturity trends can be observed in factor space, the trends do not necessarily obscure the source rock interpretations. Also, since bacterial degradation of crude oils rarely affects tricyclic terpanes, biodegraded oils can be used in predicting source rock features. The precision to which source rock depositional environments are determined might be increased with the addition of other biomarker (e.g., steranes) and stable isotope data using multivariate statistical techniques.     

Taphonomy of a South African cave: geological and hydrological influences on the GD 1 fossil assemblage at Gondolin,a Plio-Pleistocene paleocave system in the Northwest Province,South Africa

Occasional excavation of in situ and ex situ deposits at the formerly mined Gondolin paleocave system has yielded large and diverse samples of Plio-Pleistocene faunas, including isolated hominin and non-hominin primate remains. In 2003, new excavations into naturally decalcified, in situ sediments near the GD 1 datum point near the northwest corner of the cave system were undertaken. This paper describes the recovered faunal remains, taphonomy of the assemblage, and the geological and paleomagnetic context of the GD 1 deposits. The deposits represent a series of inter-stratified speleothem, in-washed sediments and talus deposits we suggest date to a time period prior to, and just after, the Olduvai normal-polarity event at around 1.7–1.8 Ma. Surface sediments and clasts were introduced into the cave by rain water runoff entering a vertically-oriented entrance that had formed along a rift in the area of GD 1. The faunal assemblage consists primarily of fragmentary diaphyseal fragments and isolated teeth. Taxonomically, the small collection of specifically identifiable bovid and equid fossils is generally consistent with remains previously excavated from in situ deposits in the Gondolin paleocave system (GD 2) and dated to around 1.8 Ma; however, the depositional histories of these two assemblages from Gondolin are remarkably different. The preservation and relative proportions of recovered skeletal elements at GD 1 is consistent with these materials having been initially accumulated outside the karstic system near the vertical cave entrance, and then later hydrologically sorted and deposited inside the cave. The sporadic to continuous water flow into the northwest corner of the cave system during the Pleistocene gradually decalcified the excavated fossilbearing breccias and further modified the composition and spatial distribution of the fossil assemblage by introducing potentially younger deposits and skeletal materials. This study highlights the variation in taphonomic processes that can occur within a single cave system, and the complex pre- and postdepositional geological and hydrological processes that can influence the taphonomic history of South African Plio-Pleistocene karstic fossil assemblages.     

A checking method for probabilistic seismic-hazard assessment: case studies on three cities

The conventional Cornell’s source-based approach of probabilistic seismic-hazard assessment (PSHA) has been employed all around the world, whilst many studies often rely on the use of computer packages such as FRISK (McGuire FRISK—a computer program for seismic risk analysis. Open-File Report 78-1007, United States Geological Survey, Department of Interior, Washington 1978) and SEISRISK III (Bender and Perkins SEISRISK III—a computer program for seismic hazard estimation, Bulletin 1772. United States Geological Survey, Department of Interior, Washington 1987). A “black-box” syndrome may be resulted if the user of the software does not have another simple and robust PSHA method that can be used to make comparisons. An alternative method for PSHA, namely direct amplitude-based (DAB) approach, has been developed as a heuristic and efficient method enabling users to undertake their own sanity checks on outputs from computer packages. This paper experiments the application of the DAB approach for three cities in China, Iran, and India, respectively, and compares with documented results computed by the source-based approach. Several insights regarding the procedure of conducting PSHA have also been obtained, which could be useful for future seismic-hazard studies.     

多元统计法在河水主要离子含量变化特征及来源分析中的运用——以梧州水文站控制断面为例

文章利用2011年4月到2012年3月对梧州水文站控制断面进行的定期采样数据,分析了该断面河水中主要阴、阳离子的化学组成,并运用多元统计分析方法研究和探讨了河水化学组成变化特征。结果表明,梧州水文站控制断面河水水化学类型以Ca2+ + HCO3-型为主,Na+、Ca2+、Mg2+、HCO3-、SO42-、NO3- 主要来源于岩石的风化,K+ 、Cl-来自于人类活动的输入;河水中离子化学组成受水—岩作用和土壤表面离子交换作用影响,对河水溶质的贡献率分别为69.34％、17.10％。