宁波市地下空间开发利用地质环境适宜性评价

随着城市化建设快速推进,地下空间资源开发是解决城市土地资源紧张的合理途径,而地质环境适宜性评价对地下空间的开发利用具有至关重要的作用。本文分析了城市地下空间开发利用地质环境适宜性评价的影响因素,运用层次分析法确定岩土体特征、水文地质条件、环境地质问题、技术经济等指标因素的权重,建立模糊综合评价模型,定量评价宁波东部新城浅层(-15~0m)和中层(-30~-15m)的地下空间开发利用地质环境适宜程度。评价结果显示,东部新城地下空间开发地质环境适宜性等级分为Ⅱ级较适宜和Ⅲ级较不适宜,并根据不同的适宜等级提出了地下空间开发利用方式,为宁波东部新城的地下空间开发利用提供依据。     

Stability and capsizing analysis of nonlinear ship rolling in wind and stochastic beam seas

Considering the actual seaway condition, stability and capsizing of nonlinear ship rolling system in stochastic beam seas is of significant importance for voyage safety. Safe zone are defined in the phase space plan of the unperturbed Hamilton system to qualitatively distinguish ship motions as capsize and noncapsize. Capsize events are defined by solutions passing out of the safe zone. The probability of such an occurrence is studied by virtue of the random Melnikov function and the concept of phase space flux. In this paper, besides conventional wave excitation, the effect of wind load is also taken into account. The introduction of wind load will lead to asymmetry, in other words, it transforms the symmetric heteroclinic orbits into asymmetric homoclinic orbits. For asymmetric dynamical system, the orbital analytic solutions and its power spectrum are not readily available, and the technique of discrete time Fourier transformation (DTFT) is used. In the end, as verification of theoretical critical significant wave height, capsizing probability contour diagram is generated by means of numerical simulation. The contour diagram shows that these analytical methods provide reliable and predictive results about the likelihood of a vessel capsizing in a given seaway condition.     

Vast amount of accommodation space controlled evolution of a continuous Pliocene–Pleistocene mixed cool-water carbonate-siliciclastic prograding wedge in the Bay of Oran (Western Mediterranean)

The Bay of Oran is part of the northern Algerian continental margin, located in the Western Mediterranean Sea between Europe and northern Africa. A regional terrace in ca. 320 m water depth described in earlier studies and a second deeper located one (∼1200 m water depth) provide an unusually vast amount of accommodation space for an observed prograding wedge. Seismo-stratigraphic interpretation of high-resolution reflection seismic data show different phases of mixed cool-water carbonate-siliciclastic deposition: (Ia) Initial aggradation with low dipping foreset deposition during early-Pliocene relative sea-level highstand. (Ib) Deposition transitions to progradation when aggradation reaches the base level. (IIa) Once progradation reaches the shelf break, terrace deposition is reduced to coarse fraction foreset deposits until it ceases entirely. (IIb) Finer sediments are bypassed and start to aggrade on the lower slope terrace until deposits reach the shelf terrace depth. (III) Due to accommodation space prolongation progradation recommences. Phase IIa and phase III deposits are separated by a hiatus. A drop in mean sea-level during the mid-Pleistocene will have caused the base level to fall below the upper strata, hence causing some reworking and redeposition. However, sea-level variations are not considered to be a main controlling factor of the depositional sequences. The evolution of this continuous Pliocene–Pleistocene mixed cool-water carbonate-siliciclastic prograding wedge is instead attributed to the controlling factor of this unusually vast amount of accommodation space. In closest proximity to the sea-floor, sparse recent sedimentation in form of 5–10 m thick sediment lobes can be observed in subbottom profiler data only. From a tectonic point of view, a prolongation of the Yusuf Fault into the survey area though expected by other authors could not be supported with the available dataset.     

Uncertainty analysis of space–time prisms based on the moment-design method

Space–time prism (STP) is an important concept for the modeling of object movements in space and time. An STP can be conceptualized as the result of the potential path of a moving object revolving around in the three-dimensional space. Though the concept has found applications in time geography, research on the analysis and propagation of uncertainty in STPs, particularly under high degree of nonlinearity, is scanty. Based on the efficiency and effectiveness of the moment-design (M-D) method, this paper proposes an approach to deal with nonlinear error propagation problems in the potential path areas (PPAs) of STPs and their intersections. Propagation of errors to the PPA and its boundary, and to the intersection of two PPAs is investigated. Performance of the proposed method is evaluated via a series of experimental studies. In comparison with the Monte Carlo method and the implicit function method, simulation results show the advantages of the M-D method in the analysis of error propagation in STPs.     

Evaluating the impact of visualization of wildfire hazard upon decision-making under uncertainty

The paper investigates whether the methods chosen for representing uncertain geographic information aid or impair decision-making in the context of wildfire hazard. Through a series of three human subject experiments, utilizing 180 subjects and employing increasingly difficult tasks, this research evaluates the effect of five different visualizations and a text-based representation on decision-making under uncertainty. Our quantitative experiments focus specifically on the task of decision-making under uncertainty, rather than the task of reading levels of uncertainty from the map. To guard against the potential for generosity and risk seeking in decision-making under uncertainty, the experimental design uses performance-based incentives. The experiments showed that the choice of representation makes little difference to performance in cases where subjects are allowed the time and focus to consider their decisions. However, with the increasing difficulty of time pressure, subjects performed best using a spectral color hue-based representation, rather than more carefully designed cartographic representations. Text-based and simplified boundary encodings were among the worst performers. The results have implications for the performance of decision-making under uncertainty using static maps, especially in the stressful environments surrounding an emergency.     

Interactive discovery of sequential patterns in time series of wind data

Wind speed and direction vary over space and time due to the interactions between different pressures and temperature gradients within the atmospheric layers. Near the earth’s surface, these interactions are modulated by topography and artificial structures. Hence, characterizing wind behaviour over large areas and long periods is a complex but essential task for various energy-related applications. In this study, we present a novel approach to discover wind patterns by integrating sequential pattern mining and interactive visualization techniques. The approach relies on the use of the Linear time Closed pattern Miner sequence algorithm in conjunction with a time sliding window that allows the discovery of all sequential patterns present in the data. These patterns are then visualized using integrated 2D and 3D coordinated multiple views and visually explored to gain insight into the characteristics of the wind from a spatial, temporal and attribute (type of wind pattern) point of view. This proposed approach is used to analyse 10 years of hourly wind speed and direction data for 29 weather stations in the Netherlands. The results show that there are 15 main sequential patterns in the data. The spatial task shows that weather stations located in the same region do not necessarily experience similar wind pattern. For within the selected time interval, similar wind patterns can be observed in different stations and in the same station at different times of occurrence. The attribute task discovered that the repetitive occurrences of chosen pattern indicate as regular wind behaviour at different weather stations that persisted continuously over time. The results of these tasks show that the proposed interactive discovery facilitates the understanding of wind dynamics in space and time.     

Map-Based Web Tools Supporting Climate Change Adaptation

This article discusses the state of the art in geovisualization supporting climate change adaptation. We reviewed twenty selected map-based Web tools, classified by their content and functionality, and assessed them by visual representations, interactive functions, information type, target audience, and how vulnerability and adaptation to climate change are addressed. Our study concludes that the tools (1) can be classified as data viewers with basic functionality and data explorers offering more sophisticated interactive functions; (2) mostly feature moderate or high richness of data content; and (3) predominantly target expert users.     

临沂市城市地下空间资源地质调查评价研究

临沂市城市建设发展迅速,城市面貌日新月异,但高楼密集、交通拥挤等问题也逐渐显现出来,城市建设需要更多的空间,开发利用城市地下空间已是首要解决的问题。临沂市位于沂沭断裂带与临沂单斜、平邑-方城盆地多个地质单元的交会处,断裂构造发育,地震活动强烈,地质条件复杂,城市地下空间开发的影响因素众多,该文从水文及水文地质条件、工程地质条件、环境地质条件、人类工程活动等方面对临沂城市地下空间资源地质环境适宜性进行了分析研究,提出了其主要制约因素为极其发育的活动性断裂的看法,凡是活动性断裂对地下空间开发有影响的区域,均为地下空间资源开发制约区。评价结论对于提高城市发展格局、提高城市空间利用率、指导城市空间开发利用规划具有一定的参考意义。     

赣南淘锡坑石英脉型钨矿床成矿机制探讨:来自流体包裹体的证据

赣南地区淘锡坑钨矿床是典型的大型石英脉型钨锡多金属矿床。矿体赋存于震旦系浅变质砂(板)岩,并延伸至深部花岗岩内,按空间产出位置分为内带矿体和外带矿体,包括宝山、西山、烂埂子、枫岭坑4大脉组,矿体产出各不相同,矿物组合也具有明显分带特征。在详细的岩相学研究基础上,文章选择淘锡坑主成矿期石英为研究对象,并与共生黑钨矿作对比,从空间角度开展不同脉组、不同矿体或中段的流体包裹体的对比研究。根据流体包裹体岩相学,石英包裹体类型有H_2O-NaCl型包裹体(Ⅰ型)、H_2O-NaCl-CO_2型包裹体(Ⅱ型)和纯CO_2体系裹体(Ⅲ型)及少量含石盐子晶的多相包裹体,并同时捕获贫CO_2的盐水溶液包裹体和纯CO-2气相包裹体。包裹体显微测温结果显示:内、外带石英脉气液两相的包裹体均具有较宽温度和盐度范围,外带均一温度和盐度w(NaCl_(eq))分别集中于200～220℃、1%～6%,内带均一温度和盐度w(NaCleq)分别集中于100～220℃、3%～7%,流体为中-低盐度、富含CO_2的H_2O-CO_2-NaCl体系,不同脉组不同矿脉之间对比结果均显示出多期成矿的特征。在矿脉形成过程中,流体的成分和温度在内外接触带有明显变化,表明岩体与围岩接触界面是造成淘锡坑矿床内带矿体和外带矿体的成矿条件改变的转折位置,成矿流体在此附近发生CO_2逸失引起相分离的不混溶作用是成矿的主要因素。     

3D打印技术在矿床学中的应用研究——以内蒙古乌力吉敖包萤石矿Ⅲ号矿体为例

3D打印(3D printing)是一种以三维模型为样本的快速成形技术,它通过逐层打印或粉末熔铸的方式来构造需要的立体图形。本文从3D打印技术的原理及其发展现状入手,重点列举内蒙古乌力吉敖包萤石矿,利用3D打印机打印具有现实可观性的地质体实体,探讨3D打印技术作为新兴的科技手段应用于矿床学教学与研究的应用价值和发展前景。研究发现,3D打印技术在矿体三维可视化中的应用符合地质图件立体化和3D打印技术多领域化的趋势,未来3D打印技术在地质领域的应用也有助于开拓矿床学教学和研究的新方式与新思路。