Quantitative assessment of the complexity of geological structures in terms of seismic propagators

How a wave interacts with heterogeneous media has been pursued by many geophysicists.The complexity of subsurface heterogeneities is seismologically a relative concept to wavelengths of seismic waves.A growing perception is that velocity variations,propagation angles,and computational accuracies are closely related at a variety of scales.A tentative strategy to quantitatively evaluate the complexity of subsurface heterogeneous media is presented in this article to see what scales of geological heterogeneiti...     

煤岩突出中孔深扩展与孔洞形成的阵发混沌模型

煤与瓦斯突出是煤岩-瓦斯系统远离平衡状态下的高度非线性行为,是井下开挖引发的最复杂的动力灾害。对混沌理论作了简要回顾,在该理论背景下研究煤与瓦斯突出演化过程的特性,得到煤岩系统在突出前处于嵌套层次较低的混沌态,而短暂时间内雪崩式突出一系列可简化为球壳形式的煤体形成孔洞是处于阵发混沌态有节奏的快速迭代阶段和突出停止后处于状态稳定的平衡态的认识。鉴于描述复杂性问题各类非线性映射所表现出的普适性质,在数学上可用Logistic函数 及其复合函数 为核函数的阵发混沌态迭代运算,来对突出的发生、发展和终止行为进行描述,并给出核函数中相对孔深 和突出参数 的初步形式。该研究可深化和丰富对突出物理本质的认识。     

The unintended consequences of regulatory complexity: The case of cruise tourism in Arctic Canada

The cruise tourism industry in the Canadian Arctic has the potential be an important contributor to the northern economy, but undue complexity in the permitting and regulatory process represents a major barrier to cruise operators and as a result seems to be limiting development potential and other cultural and educational benefits related to tourism in the region. Based on a set of interviews and follow-up interviews with Arctic cruise operators and government permit issuers (n=48), investigative phone calls (n=22), and follow-up verification calls (n=20+), analysis of the management system that currently governs cruise tourism in Arctic Canada is provided including recommendations for improvement. There are currently over 30 permits, approvals, and notification processes for cruise companies operating in the Canadian Arctic (collective called ‘permits and permissions'). Permits and permissions are required for vessel safety, environmental protection, gaining access to national parks, and visiting heritage and archaeological sites among others. They are issued by numerous agencies under multiple jurisdictions and statutes with no integration or organizing system. The result is a process that is overly complex, repetitious, and costly for operators. In comparison, the permitting systems in Greenland and Svalbard are more streamlined, causing some cruise companies to consider abandoning Canadian waters in favour of these less bureaucratic regions. Federal and territorial attention is required to create efficiencies in the cruise permitting process in Arctic Canada if the economic, socio-cultural, and educational benefits of the industry are to be fully realized.     

小波多分辨分析在壳幔非均匀尺度研究中的应用

利用小波的“变焦距”多分辨功能,提出了针对壳幔过渡带复杂波形的变尺度震相分析方法,将它与壳幔过渡带非均匀尺度的研究相联系,使得传统的震相识别由“静态”转变为“动态”并编写了相应的计算程序. 对玛沁—兰州—靖边地震测深剖面壳幔过渡带的Pm波形,利用复杂性系数法获得了沿剖面的2个陆-陆碰撞带,它们分别对应玛沁断裂和海原85级强震区的位置. 利用变尺度震相分析方法得到了玛沁断裂和海原地震下方壳幔过渡带的多层Pm震相. 结果表明,海原地震下方的壳幔过渡带厚度约有20km,层状清晰,它至少由3个高低速相间的层组成;玛沁断裂所对应的壳幔过渡带大约由2个较薄的层组成. 这种分层和厚度的不同表明了鄂尔多斯地块和祁连地块的接触带、巴颜喀拉地块和柴达木地块的接触带由于陆-陆碰撞的时期和相互作用的方式不同,因此在现今可分辨的壳幔过渡带结构非均匀尺度上存在明显差异.     

Interrelationships Between Topography,Quaternary Vertical Displacement,Active Faults and Short-term Horizontal Crustal Strain in Honshu,Japan

Regional and local characteristics of active fault patterns and elevation variation throughout Honshu, Japan are characterized in terms of their fractal dimensions; this allows variation in these complex variables to be compared directly to the scalar properties of net Quaternary vertical displacement, elevation and 10- and 110-year horizontal strains. The comparisons reveal that, throughout Honshu as a whole, there is significant correlation (r=0.75) between Quaternary vertical displacement, elevation, and its fractal properties. There is poor correlation, however, of elevation and its fractal properties to horizontal crustal strain, and also between Quaternary vertical displacement and horizontal crustal strain. A slight negative correlation is observed between the fractal properties of the active fault system and horizontal crustal strain measured over 10- and 110-year time periods (–0.43 and –0.26, respectively). The correlation between the 10-year (1985–1994) and 110-year (1883–1994) area strains, 0.48, reveals the occurrence of considerable change in the distribution of regional strain over these short time frames. Local computations of the correlation between data sets made for overlapping 160 km length windows of data spaced every 20 km along analysis lines reveal internal fluctuations in the correlation between variables. The local correlation between Quaternary vertical displacement and elevation is highest through central Japan and the Kinki Triangle. There is weak negative correlation between area strain and fractal dimensions of the active fault network. The local correlation between the fractal dimensions of active faults and horizontal area strain over the recent 10-year time period averages about –0.6 through central Japan in an area that extends across the Kinki Triangle through the northern part of central Honshu and northeast across the Itoigawa Shizuoka Tectonic Line. In general, regions of greatest complexity in the active fault network are associated with persistent negative area or compressional strain. Sparsely faulted areas in general coincide with areas of positive or roughly zero area strain. The presence of negative correlation through central Japan and the Kinki Triangle area in the recent 10-year period results from a decrease of area strain within an increasingly complex active fault system that reaches maximum negative values concentrated in the Kinki Triangle during the 1985–1994 time period.     

高寒湖沼区水系沉积物中元素迁移富集的分形伸展机制

水系沉积物中成矿元素迁移富集的动力学机制是复杂性科学的研究课题。利用分形理论研究空间结构复杂性特征,适宜于元素分散过程的动力学研究。从元素迁移过程的分形特征揭示出元素分散过程的分形伸展机制。并在进一步研究了元素粒级层分维特征后,得出了成矿元素物理空间结构的复杂性特征和相互联系。研究成矿元素相态层分维和其间非线性关联,揭示出成矿元素分散过程分形伸展的涌现原因。     

中国东-南部裂陷盆地断裂系统复杂性的表现形式及成因机制——以南堡凹陷和涠西南凹陷为例

中国东-南部裂陷系列盆地油气资源十分丰富,而断层的分布演化十分复杂,是油气进一步勘探开发需要解决的关键问题。本文应用广义断层模式,在大量三维地震资料构造解析的基础上,以渤海湾盆地的南堡凹陷和北部湾盆地的涠西南凹陷为例,对中国东-南部盆地复杂的断裂系统进行了解剖和归纳,并提出了伸展变形区预测断层性质的伸展应变椭圆。结果表明,中国东-南部裂陷盆地断裂系统的复杂性存在9种表现方式,从成因上进一步归纳为3个方面:(1)断层的走向和性质多样;(2)断层在平、剖面上存在复杂多变的组合形式;(3)断层形成和演化存在复杂的时-空关系。造成复杂性的根本原因是先存断裂分布的复杂性和不同方向(北西-南东向和近南北向)伸展变形的叠加。不同盆地、同一盆地不同区域应力场演化具有很大的相似性:40Ma以前,北西-南东向伸展;38Ma以来,近南北向伸展。断层分布和演化差异主要是由先存构造分布差异造成的。     

地理学视角下城市复杂性研究综述——基于近20年文献回顾

城市作为组织结构复杂的开放人地地域系统,一直是地理学的研究核心之一。论文以2000—2020年相关文献为数据源,构建一套定量分析与定性认知相结合的文献分析判读体系,基于地理学视角从概念内涵、研究主题、技术方法等方面综述城市复杂性研究成果并开展讨论。过去20 a来,中国的城市复杂性研究逐渐从单尺度的格局、过程和机制研究转向于多尺度下复杂交互过程的集成与综合研究,并逐步形成了城市设施网络、城市人居环境、城市经济活动以及城市空间治理4个主要主题,在数据方法上逐步转向于空间技术及社会计算支持下的全景式全生命周期数据支撑的多维场景化分析。今后及未来一段时期,地理学视角下的城市复杂性研究需要进一步加强城市数字基础设施建设及全周期信息采集能力,加深对城市生态经济体系的综合测度及监控,增强跨区域发展机制影响下的城市流空间研究。     

Information and complexity measures applied to observed and simulated soil moisture time series

Abstract

Time series of soil moisture-related parameters provide important insights into the functioning of soil water systems. Analysis of patterns within such time series has been used in several studies. The objective of this work was to compare patterns in observed and simulated soil moisture contents to understand whether modelling leads to a substantial loss of information or complexity. The time series were observed at four plots in sandy soils within the USDA-ARS OPE3 experimental watershed, for a year; precipitation and evapotranspiration (ET) were measured and estimated, respectively, and used for soil water flow simulation with the HYDRUS-1D software. The information content measures are the metric entropy and the mean information gain, and complexity measures are the fluctuation complexity and the effective measure complexity. These measures were computed based on the binary encoding of soil moisture time series, and used probabilities of patterns, i.e. probabilities of joint or sequential appearance of symbol sequences. The information content of daily soil moisture time series was much smaller than that of rainfall data, and had higher complexity, indicating that soil worked essentially as an information filter. Information content and complexity decreased and increased with depth, respectively, demonstrating the increase in the information filtering action of soil. The information measures of simulated soil moisture content were close to those of the measurements, indicating the successful simulation of patterns in the data. The spatial variability of the information measures for simulated soil moisture content at all depths was less pronounced than the one of measured time series. Compared with precipitation and estimated ET, soil moisture time series had more structure and less randomness in this work. The information measures can provide useful complementary knowledge about model performance and patterns in observation and modelling results.

Citation Pan, F., Pachepsky, Y. A., Guber, A. K., & Hill, R. L. (2011) Information and complexity measures applied to observed and simulated soil moisture time series. Hydrol. Sci. J. 56(6), 1027–1039.     

朱仙庄矿断裂分形研究及其对瓦斯赋存的控制

在系统分析断裂构造的基础上,应用分形理论与方法,采用盆维数法对朱仙庄煤矿断裂网络进行复杂程度评价。评价结果表明:矿井断裂构造总体偏于复杂,分维值大于1.2的复杂单元约占总数的66.7%,研究区东南部和中偏北部构造偏于简单。通过对分维值与断裂构造的对比研究,认为分维值是评价朱仙庄矿断裂网络复杂程度较为可靠的指标,8煤层瓦斯含量以F10断裂为界呈现北低南高的趋势,与分维值耦合较好,表明分维值可作为矿井瓦斯突出预测的指标之一。