Aesthetic evaluation of yardang landforms landscape: the Dunhuang Yardang National Geo-park example

Dunhuang Yardang National Geo-park,situated in the Gansu Province of northwestern China(40o25'36 "N–40o33'10" N,93o00'00 "E–93o13'30" E),was chosen as a research locality of aesthetics evaluation of yardang landforms landscape.The yardang landforms landscape is a composite structural system of patch-corridor-matrix,with four landscape unit elements as dense group,sparse group,single body and remnant.The study of the landscape aesthetics spatial pattern of Dunhuang Yardang National Geo-park shows that yardang dense group,sparse group and single body provide the greatest contribution to the aesthetic value of yardang landforms landscape.Yardang bodies are scarce,unique,irreplaceable,and priceless resources in yardang landforms areas.However,they are easily destroyed under the influence of the natural and artificial factors.Therefore,when the tourism potential of yardang landforms landscape is exploited,the protection should be fully improved.     

中国南方湿润区红层地貌及相关问题探讨

我国红层出露面积广大,但地学界对红层关注不足,各学科对红层问题的研究缺乏融合,存在着＂多张皮＂的问题;尤其是对红层这个特殊的脆弱地理单元的土地退化及生态环境问题缺少关注。南方湿润区是我国红层集中分布区之一,大部分红层区存在着严重的地貌灾害和水土流失问题,甚至分布着许多＂红层荒漠＂。红层区的土地退化虽与人的不合理利用关系...     

辽宁沿海经济带产业分工研究

为反映区域产业分工现状,利用变异系数与空间洛伦茨曲线、空间基尼系数相结合,在产品层次上,对辽宁沿海经济带产业分工现状进行定量研究并提出相应的协调发展建议。结果表明：辽宁沿海经济带农业和采掘业依据自身比较优势发展相应产业,产业分工较为明确;制造业在行业层次存在同构现象,但在产品层次上,各地差异化发展明显,区域产业分工逐步显现;第三产业内部结构亟待调整,其中基础服务业与个人消费服务业发展较为完善,但生产和市场服务业中的金融、物流和专业技术服务业与公共服务业中的公共管理服务业发展相对滞后,影响工业化进程的推进与产业结构的升级。在此基础上,针对各产业分工结果,提出相应的协调发展建议。     

柴达木盆地东北部哈勒腾河流域风况特征及其对风沙地貌发育的影响

风况是影响风沙地貌发育的重要因子,在一定程度上决定了沙丘类型.为探究区域风沙地貌发育与风况之间的关系,对哈勒腾河流域不同区域一个完整年度的风况进行分析.结果表明:流域年平均风速为2.78 m·s-1,起沙风集中在春夏季,平均风速为7.78 m· s-1,起沙风事件平均持续时间为4.1 h;流域输沙势122-254 VU...     

A probabilistic approach to the inversion of data from a seismic array and its application to volcanic signals

Array techniques are particularly well‐suited for detecting and quantifying the complex seismic wavefields associated with volcanic activity such as volcanic tremor and long‐period events. The methods based on the analysis of the signal in the frequency domain, or spectral methods, have the main advantages of both resolving closely spaced sources and reducing the necessary computer time, but may severely fail in the analysis of monochromatic, non‐stationary signals. Conversely, the time‐domain methods, based on the maximization of a multichannel coherence estimate, can be applied even for short‐duration pulses. However, for both the time and the frequency domain approaches, an exhaustive definition of the errors associated with the slowness vector estimate is not yet available. Such a definition become crucial once the slowness vector estimates are used to infer source location and extent. In this work we develop a method based on a probabilistic formalism, which allows for a complete definition of the uncertainties associated with the estimate of frequency–slowness power spectra from measurement of the zero‐lag cross‐correlation. The method is based on the estimate of the theoretical frequency–slowness power spectrum, which is expressed as the convolution of the true signal slowness with the array response pattern. Using a Bayesian formalism, the a posteriori probability density function for signal slowness is expressed as the difference, in the least‐squares sense, between the model spectrum and that derived from application of the zero‐lag cross‐correlation technique. The method is tested using synthetic waveforms resembling the quasi‐monochromatic signals often associated with the volcanic activity. Examples of application to data from Stromboli volcano, Italy, allow for the estimate of source location and extent of the explosive activity.     

Model of a strong volcanic blast and a method of estimating the mass ejected

A hydrodynamic model of a strong volcanic blast associated with large (caldera-forming) ash–gas-flow eruptions is presented. We show that the mass erupted from a vent influences considerably the damping of the shock wave. If the ejected mass flux is constant, the shock amplitude as a function of distance will decrease slower (in accordance with the inverse 4/3 power law) than that of an atomic explosion (the inverse cube power law). From the modelling, we extract a relation connecting the effective energy of a blast with the mass ejected during the blast phase. The mass released during the largest explosion of the 1883 eruption of Krakatau, and the lateral blast energy at Mount St. Helens on 1980 May 18 are estimated on the basis of the equation obtained.     

Structure of volcanic landscape in the equatorial belt (A case study of the Kerinci Volcano,Sumatra Island)

An analysis is made of the volcanic landscape structure of Mount Kerinci, the highest volcano in South-East Asia. Field observations, remote sensing methods, and also cartographic material were used in obtaining new evidence to gain a more penetrating insight into the characteristics of structure and altitudinal zonation of the landscapes along the equatorial belt that have shaped themselves and are evolving in conditions of intense volcanic activity, equatorial climate and heavy anthropogenic load. The analysis revealed natural and anthropogenic landscape-forming factors that determined the present-day landscape appearance of the Kerinci volcano. Within the boundaries of the volcanic structure, landscapes of the mountain class show the highest diversity of landscape taxa. They are represented largely by slope units. With an increase in altitude, there is an increase in the proportion of landscapes of steep and vertical slopes as well as moderately steep slopes, along with the disappearance of landscapes of smart slopes and valley bottoms. A less diverse landscape structure is characteristic for subclasses of aggraded-denudation plains where there occur only landscapes with bogs and waterlogged meadows predominating. Anthropogenic modifications of landscapes occur mostly within subclasses of smart slopes and aggraded-denudation plains. They are characterized by a predominance of agricultural plants.     

Land use/cover, landforms and fragmentation patterns in a tropical dry forest in the southern Pacific region of Mexico

In spite of widely documented studies of deforestation rates and land use/cover changes in tropical dry forests in Mexico, relatively little is known about fragmentation patterns in such forests. This study defines the spatial distribution of landforms and land use/cover types the lower Papagayo River basin and examines their influence on fragmentation patterns and biological diversity in a tropical dry forest in that southern Pacific region. The land use/cover map was constructed from aerial photographs, Landsat TM imagery (2000) and fieldwork. Landform units were defined based on altitude, slope, lithology and morphology. Landscape fragmentation parameters were obtained using FRAGSTATS (version 3.3) considering the numbers of patches, mean, minimum and maximum patch size, edge density, total edge and connectivity. Results show tropical dry forest to be remnant vegetation (~11 per cent), characterized by isolation and low connectivity. Land use/cover types have different effects on fragmentation patterns. Agriculture and cattle raising produce similar numbers of patches, but with a different mean size; and human settlements have a scattered distribution pattern. The abandonment of rural agricultural livelihoods has favoured the expansion of secondary tropical dry forest characterized by continuity and high connectivity, which suggests a high regeneration potential from land abandonment. It can be concluded that tropical dry forest fragmentation and recovery at regional scales depend on such landscape attributes as lithology, slope, geomorphology and management.     

Use of magnetic hysteresis properties and electron spin resonance spectroscopy for the identification of volcanic ash: a preliminary study

This initial study investigates the possible use of hysteresis parameters and electron spin resonance (ESR) spectroscopy to identify and correlate volcanic ash. ESR and hysteresis properties are sensitive to characteristics such as the chemical composition, mineralogy, and grain size and shape. These characteristics are determined by the tectonic setting of the volcano and by the magmatic and eruptive history of the volcanic ash. Hysteresis properties and ESR spectra, therefore, should be distinct for each ash eruption and may help to identify the eruptive source of the ash and to correlate ash from unknown sources. We conducted ESR spectroscopy at room temperature and magnetic hysteresis measurements on 19 samples of a single ash, the 1974 October 14 eruption of the Fuego volcano, Guatemala, and on single samples of ash obtained from eight different volcanoes. The Fuego ash samples were obtained at increasing distances from the volcano. For the single Fuego ash, ESR spectra and hysteresis parameters become increasingly similar as the distance from the volcano increases. At distances greater than 30 km, ESR spectra and hysteresis properties are uniform. The variability of magnetic and ESR properties with distance from Fuego is due to the preferential fall-out of phenocrysts closer to the volcano. At large distances, the ash is more uniform, containing more glass and microcrystals. All eight ash samples from the different volcanoes can be distinguished from the distal Fuego 1974 October 14 ash using ESR spectra and hysteresis parameters. These results suggest that ESR and hysteresis measurements have a potential to be used as tools to identify distal ash when used in conjunction with geochemical, mineralogical and/or other types of data.     

美国波士华交通经济带的形成与演化

本文研究了美国波士华交通经济带的形成与演化过程，分析了在不同阶段美国波士华交通经济带的生命周期特征，认为美国商业资本主义、产业资本主义的发展、高速公路的发展以及带来的集聚与扩散作用、经济服务化分别在美国波士华交通经济带的形成、发展和演化等不同阶段扮演着重要角色。波士华交通经济带是美国最大、发展最早的交通经济带，研究该地区的演化规律对我国交通经济带发展也具有借鉴作用。     

日本东海道交通经济带形成和演化机制研究

本文研究了日本东海道交通经济带形成和演化的背景以及时空模式，分析了不同阶段东海道交通经济带形成和演化的特点和主要动力机制，并在此基础上，探讨了高速交通体系对交通经济带内产业空间演化的作用。     

A fault scarp in an urban area identified by LiDAR survey: A Case study on the Itoigawa–Shizuoka Tectonic Line, central Japan

A light detection and ranging (LiDAR) survey was conducted in a densely built-up area to generate a high-resolution digital elevation model (DEM) to look for active faults. The urban district of Matsumoto City in central Japan is located in a 3-km² basin along the Itoigawa–Shizuoka Tectonic Line active fault system, one of Japanese onshore fault systems with the highest earthquake probability. A high-resolution DEM at a 0.5-m-grid interval was obtained after removing the effects of laser returns from buildings, clouds and vegetation. It revealed a continuous scarp, up to ~ 2 m in height. Borehole data and archaeological studies indicate the scarp was formed during the most recent faulting event associated with historical earthquakes. In addition, the fault scarp strongly supports that the urban district is in a pull-apart basin related to a fault step-over between two left-lateral strike-slip faults. Consequently, accurate interpretation of fault geometry is crucial to provide estimates of future surface deformation and to allow modeling of basin structure and strong ground motion. Thus, the LiDAR mapping survey in urban districts is effective for detailed active fault mapping in order to constrain basin structure and to forecast the exact location of surface rupturing associated with large earthquakes.