Glossary of fault and other fracture networks

Increased interest in the two- and three-dimensional geometries and development of faults and other types of fractures in rock has led to an increasingly bewildering terminology. Here we give definitions for the geometric, topological, kinematic and mechanical relationships between geological faults and other types of fractures, focussing on how they relate to form networks.     

HDF 5格式特点及其对遥感数据格式标准化的几点启示

阐述了HDF 5数据格式的特点及其对遥感数据标准化的启示和借鉴作用。HDF 5格式层次式的逻辑结构、B树的物理存储方式，面向对象的特性、数据类型的广泛支持、自我描述以及内容与表达的分离等特点，使得它在记录和存储科学数据时具有强大的优势。遥感数据标准化如何设计一种结构简单且扩展性很好，同时支持不同平台的标准格式，可以从HDF 5的实现方法上得到借鉴。     

Complex geometry and segmentation of the surface rupture associated with the 14 November 2001 great Kunlun earthquake, northern Tibet, China

The 14 November 2001 Kunlun, China, earthquake with a moment magnitude (M_w) 7.8 occurred along the Kusai Lake–Kunlun Pass fault of the Kunlun fault system. We document the spatial distribution and geometry of surface rupture zone produced by this earthquake, based on high-resolution satellite (Landsat ETM, ASTER, SPOT and IKONOS) images combined with field measurements. Our results show that the surface rupture zone can be divided into five segments according to the geometry of surface rupture, including the Sun Lake, Buka Daban–Hongshui River, Kusai Lake, Hubei Peak and Kunlun Pass segments from west to east. These segments, each 55 to 130 km long, are separated by step-overs. The Sun Lake segment extends about 65 km with a strike of N45° 75°W (between 90°05′E 90°50′E) along the previously unrecognized West Sun Lake fault. A gap of about 30 km long exists between the Sun Lake and Buka Daban Peak where no obvious surface ruptures can be observed either from the satellite images or field observations. The Buka Daban–Hongshui River, Kusai Lake, Hubei Peak and Kunlun Pass segments run about 365 km striking N75° 85°W along the southern slope of the Kunlun Mountains (between 91°07′E 94°58′E). This segmentation of the surface rupture is well correlated with the pattern of slip distribution measured in the field. Detailed mapping suggest that these five first-order segments can be further separated into over 20 second-order segments with a length of 10–30 km, linked by smaller scale step-overs or bends.Our result also shows that the total coseismic surface rupture length produced by the 2001 Kunlun earthquake is about 430 km (excluding the 30-km-long gap), which is the longest coseismic surface rupture for an intracontinental earthquake ever recorded.Finally, we suggest a multiple bilateral rupture propagation model that shows the rupture process of the 2001 M_w 7.8 earthquake is complex. It consists of westward and eastward rupture propagations and interaction of these bilateral rupture processes.     

准噶尔盆地车38井区地震物理模型技术研究

利用地震物理模型技术,依据准噶尔盆地车38井区三维地震的地质解释成果,按一定的模拟相似比,制作一个三维物理模型.利用超声波反射技术,用2种观测系统对模型进行全三维数据采集.通过不同面元三维数据效果对比,提供针对不同地质目标确定面元大小的试验依据,提出从野外采集、资料处理到解释的成套方案.根据不同地震地质条件和勘探目标要求,应用模型正演技术可以指导合理确定三维地震勘探面元大小和其它采集参数.     

计算几何算法在GIS图形分析中的应用

图形空间分析是地理信息系统的重要功能之一。根据地理信息系统应用领域的不同。所需的图形空间分析功能也不尽相同，但是，各种图形空间分析功能所涉及到的基本图形关系的判断确基本相同。文中介绍并改进了一些计算几何方法在ＧＩＳ常用图形分析中的应用。目的在于抛砖引玉，让更多的人开展这方面的研究。     

LiDAR-based fluvial remote sensing to assess 50–100-year human-driven channel changes at a regional level: The case of the Piedmont Region,Italy

Remote Sensing (RS) technology has recently offered new and promising opportunities to analyze river systems. In this paper, we present a calibration of characteristic Hydraulic Scaling Law (HSL) using a regional database of river geomorphic features. We consistently linked discharge with channel geometry features for estimated Bankfull Channel Depth (eBCD), Active Channel Width (ACW), and Low Flow water Channel Width (LFCW), which are continuously available from RS data along the river course. We then used historical information and external sources of information on channel reaches that were relatively unaffected by human pressure over periods ranging from a few decades to a century (measured in comparable geographical areas) to infer relatively Unaltered HSLs (rUHSLs). Adopting rUHSL validated with available local historical evidence on channel geometry, we were able to assess historical changes in channel geometry consistently over the entire region and within the studied temporal window. The case study was conducted for the Po basin in the Piedmont Region, north-west Italy. From our analysis, it emerges that regionally 74% of the river network has riverbed incisions exceeding 1 m, while 66% of channels have halved their historical widths with a total of 617 ha of land subtracted from the active channel. LFCW is, on average, wider in Alpine rivers compared with those located in the North Apennines. Although it is currently not possible to measure the accuracy of these estimates, the evidence generated is coherent with available historical information, characteristic hydraulic scaling laws, evidence from relatively unaltered reaches and the available literature on local fluvial systems. This methodology provides robust, novel and quantitative information regarding decadal to secular channel changes that have occurred on a regional scale. This new layer of information enriches our ability to rationally address assessments of large-scale past and future channel trajectories. © 2018 John Wiley & Sons, Ltd.     

Facies architecture and heterogeneity of the fluvial–aeolian reservoirs of the Sergi formation (Upper Jurassic), Recôncavo Basin,NE Brazil

The Sergi Formation (Upper Jurassic) represents the main hydrocarbon reservoir of the Recôncavo Basin, Brazil. The basal vertical facies succession of the Sergi Formation comprises reservoirs formed by a complex fluvio–aeolian–lacustrine interaction. Facies architecture and detailed petrophysical analysis of these reservoirs have enhanced the understanding of heterogeneity at a variety of scales and has allowed the development of predictive models that describes the range of styles of mixed fluvial–aeolian reservoirs. At megascopic scale, the reservoirs are predominantly composed of sand bodies deposited by fluvial channel and aeolian facies associations. Regional flooding surfaces and sequence boundaries are their main flow barriers. The regional flooding surfaces are composed of fine-grained sediments deposited by lacustrine facies associations and the sequence boundaries act as flow barriers due to mechanically infiltrated clays. Based on its geometrical relations, reservoirs linked to fluvial–aeolian–lacustrine interaction formed two types of reservoirs at macroscopic scale: (i) with good lateral continuity of aeolian packages and relatively simple stratigraphic correlation and (ii) of highly compartmentalized aeolian packages with complex stratigraphic correlation and truncation by fluvial deposits. Mesoscopic heterogeneity reflects lithofacies, sedimentary structures, and lamina-scale variability within aeolian and fluvial facies associations.     

Geometry and kinematics of the Mosha Fault, south central Alborz Range, Iran: An example of basement involved thrusting

Field investigation of the western part of the Mosha Fault in several structural sections in the south central Alborz Range showed that the fault has a high angle of dip to the north, and emplaces Precambrian to Cenozoic rocks over the Eocene Karaj Formation. Study of the kinematics of the Mosha Fault in this area, based on S–C fabric and microstructures, demonstrates that it is a deep-seated semi-ductile thrust. Strain analysis on rock samples from different sections across the Mosha Fault shows a flattening pattern of deformation in which the long axis of the strain ellipsoid is aligned in the fault shear sense. The Mosha Fault is associated with a large hanging-wall anticline, cored by Precambrian rocks, and series of footwall synclines, formed of late Tertiary rocks. This geometry, together with several low angle short-cut thrusts in the fault footwall, implies that the Mosha Fault is an inverted normal fault which has been reactivated since the late Tertiary. In the study area, the reverse fault mechanism was associated with the rapid uplift and igneous activity in the central Alborz Range during the late Tertiary, unlike in the eastern portion of the fault, where the fault kinematics was replaced by a strike-slip mechanism in the Late Miocene.     

On geometric design considerations and control methodologies for absorbing wavemakers

This paper investigates the effects that geometry and control have on the absorption characteristics of wavemakers. It presents the hydrodynamic coefficients for piston and bottom hinged flap wavemakers and also for two novel wavemaker profiles. Absorption efficiencies are presented for wavemakers using one, two and three control coefficients for reactive control. This is then used to analyse the absorption efficiency of each of the different wavemakers based upon the geometry and the control strategy used. It is shown that the amount of absorption for a given paddle differs greatly depending on the choice of control coefficients used to implement complex conjugate control. Increased absorption can be achieved over a broader bandwith of frequencies when the geometry of the wavemaker is optimised for one specific frequency.     

参数法与面束法——两种既对立又统一的方法

数学分析中两种最基本的运算——微分与积分,来自化整为零与积零为整的想法。化整为零的想法,几何中就是参数法。积零为整的想法,在平面几何中,就是线束法;在空间几何中,就是面束法。参数法与面束法是两种既对立又统一的方法。