首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
我国考古地球物理学的发展   总被引:1,自引:0,他引:1  
考古地球物理学是一门自然科学与社会科学交叉的边缘学科.从考古地球物理的社会需求及国外考古地球物理发展的状况出发,论述了我国考古地球物理学的发展历程和趋势.详细介绍了我国地球物理工作者结合长江三峡库区故陵楚墓的勘查,对考古地球物理的方法进行了大规模的试验研究,为解决楚故陵是否存在的问题提供了重要依据;也是一个以任务带学科发展的典型事例.  相似文献   

2.
我国环境问题与环境地球物理学   总被引:1,自引:0,他引:1  
从环境和环境问题出发,简述了环境地球物理学的形成过程,并定义环境地球物理学为:应用地球物理学的理论和方法,研究解决环境保护、改善和治理方面问题的一门地球物理分支学科.文章叙述了全球和我国当前的主要环境问题,论述了环境地球物理学在解决这些问题中所起的重要作用;介绍了我国环境地球物理学在研究解决某些环境问题中的应用事例;并在分析我国对环境地球物理的需求以及满足这种需求的能力之后指出,我国环境地球物理工作者必将为我国和世界环境问题的解决及学科的发展做出应有的贡献.  相似文献   

3.
    
In bolsons in the desert regions of southern California and adjacent parts of Nevada, the area underlain by alluvial fan gravels and playa sediments is generally ?1·2 times the area being eroded to produce those sediments. In certain larger basins in the vicinity of Death Valley, however, the depositional area is only about half the size of the erosional area. This reflects the more active tectonic environment in these bolsons. Of the areas underlain by recent sediments in these bolsons, playas make up 2–6 per cent. Smaller playas are found in the Mojave region, and seem to be associated with sedimentary terranes. Conversely, igneous terranes support larger playas. Larger deviations of playa area from these averages are attributable to incorrect identification of bolson boundaries. Fine sediment is either able to pass through the bolson to the next down stream, or is being collected from areas upstream that were not considered to be part of the system. For example, the playa in Death Valley is unusually large. This is in part because the Death Valley playa has been deformed tectonically so parts of it are now eroding, and in part because the outlet of Lake Tecopa was downcut in the geologically recent past, so sediment once trapped there now reaches Death Valley. The size of the playa in Death Valley is still adjusting to these changes.  相似文献   

4.
A morphostructural analysis has been performed on the eastern flank of Mt Etna, located between the towns of St. Alfio and Linera and the Ionian Sea. The research has been carried out through analysis of aerial photographs, and has allowed recognition of morphoneotectonic elements such as: some scarps with rectilinear trend, laterally becoming morphological flexures, according to the lithology; anomalies in the hydrographic network, such as rectilinear tracts of drainage, valleys with simple or double bends, hanging valleys and truncated valleys, narrow deeply engraved valleys with meanders and fluvial captures. All these elements are caused by a fault system oriented NNW–SSE, with a mainly vertical component. Seismic events with very shallow foci have been recorded in the study area; these earthquakes triggered several small landslides on the fault scarps and large series of coseismic and coaxial fractures. It is possible to show that the morphostructures examined have been reactivated during many of the seismic events that have occurred in the area. The combination of these elements verifies that the morphostructures have a real neotectonic cause, which is associated with uplifts which have occurred in the area at different times.  相似文献   

5.
地质雷达是探测地雷的有前途的技术方法之一。影响地质雷达探测地雷能力的因素很多,其中有:1)地雷材料(金属的或塑料的)的类型;2)周围土壤的条件(土壤结构和土壤中水分);3)所用的雷达频率。通过对地雷与围岩土壤之间的介电常数以及雷达波衰减的影响的研究调查了影响地质雷达探测地雷能力的几个因素从理论上评价和模拟了每一种因素的影响。发现雷达探测地雷的能力很大程度上与雷达类型、土壤含水量和结构,以及雷达频率有关。在任何土壤条件与雷达频率下,金属雷达比塑料雷达容易探测。不考虑土壤结构, 随着土壤中水分增大,对塑料雷达的探测变得容易,而对金属地雷探测难度增大。土壤中泥土含量比例增大引起与水分增大同样的影响。然而只要土壤中泥土和水分比例较低,较高雷达频率可以得到较好的地雷探测结果。研究结果有助于依据地雷类型和环境条件来选择最佳的雷达天线与数据采集参数。  相似文献   

6.
随着近代观测和实验技术的发展,人们越来越重视对地球运动及其机理的认识,并注意到大地测量学与地球物理学和地球动力学的联系与渗透。本文将对以上三者的联系以及大地测量学在监测地球运动和研究地球动力事件中的作用作一综述,并对近年国内外这方面的研究进展作一介绍。  相似文献   

7.
    
Crude oils produced in the North West shelf of Western Australia are highly volatile, a characteristic not shared by most of the Northern Hemisphere crude oils on which internationally accepted toxicity test protocols were developed. Because of this volatility and some other factors, the LC50 and EC50 values obtained from acute toxicity tests will be significantly affected by the changes of toxicant concentration in test solutions during the period of exposure. To address these issues all steps of a standard protocol for crude oil toxicity testing have been revised. A systematic study has been performed on factors which affect petroleum hydrocarbon solubilisation in aqueous systems during test solution preparations. The influence of mixing time, agitation energy and volume/interface ratio on a hydrocarbon concentration in a water-soluble fraction (WSF) was studied for heavy, medium and light crude oils. A study of the sensitivity of marine unicellular algae to WSF of crude oils was conducted with Isochrysis sp., Nannochloropsis-like sp. and Nitzchia closterium. Total concentrations of hydrocarbons dissolved in test solutions were estimated by UV-spectrometry and GC/FID chemical analyses. When the toxicant concentration decreased during the exposure period, the EC50 values derived from initial or final concentrations either underestimate or overestimate toxicity, respectively. Therefore, weighted average concentrations (WAC) calculated for the whole test period were recommended for expressing hydrocarbon concentrations in test solutions of crude oils. Toxicity indices calculated from WAC of total hydrocarbons for different crude oils can be compared regardless of the rates of hydrocarbon loss.  相似文献   

8.
Some of the reasons are given for the editorial (Richards, 1990) now discussed by Rhoads (1994) and Bassett (1994). These include the lack of interest generally displayed by geomorphologists in matters of scientific philosophy and method, and the instrumentalist view of research often presented to postgraduate students given present funding imperatives. It is suggested that in a revision of views about the validity of a hypothesis-testing, critical rationalist methodology might have considerable implications for the practice of environmental sciences, and that accordingly the debate initiated by Rhoads and Bassett is worthy of continuation.  相似文献   

9.
The cumulative probability distributions for stream order, stream length, contributing area, and energy dissipation per unit length of channel are derived, for an ordered drainage system, from Horton's laws of network composition. It is shown how these distributions can be related to the fractal nature of single rivers and river networks. Finally, it is shown that the structure proposed here for these probability distributions is able to fit the observed frequency distributions, and their deviations from straight lines in a log-log plot.  相似文献   

10.
RIS-K2型探地雷达在广州市管线普查中的应用   总被引:1,自引:0,他引:1  
探地雷达作为一种新的探测方法,在城市管线探测过程中得到了越来越广泛的应用。本文结合RIS-K2型探地雷达在广州市管线普查中的实际应用,阐明了探地雷达的工作原理和方法,并得到了一些有意义的结论。  相似文献   

11.
地球物理学在生态环境及其相关领域中的应用   总被引:6,自引:1,他引:5  
多年来应用地球物理学以地球的岩石圈为研究对象,为矿产资源的勘查和开发提供了理论、方法和手段。而地球科学的功能应该还包括防止地质灾害、保护生态环境、认识地球等。本文从六个方面(地下水及地表水体污染的测量和监控、评价工业区的生态环境,城市中的地球物理监测,查明废弃弹药隐藏地区的位置,监测核爆炸以及监测地震和其它地质灾害等)论述了地球物理学在生态环境及其它领域中的应用。  相似文献   

12.
深度学习是机器学习的一个分支,是使用低维特征组合来表示高维特征组合,包含多重复杂结构或多个非线性变换的多个处理层对数据进行高维抽象的一种算法.深度学习的自我学习和适应能力使它在计算机视觉、语音识别、金融等领域得到了广泛应用.为分析深度学习在地球物理领域的应用前景,本文在介绍深度学习概况的基础上,结合实例分析了深度学习在地震探测定位、大地电磁数据处理、航空电磁数据解释等领域的应用现状.发现深度学习在处理海量数据在并行处理、进行模式识别特征提取、数据预测等方面都有巨大的优势.随着三维探测逐渐成为地球物理勘探主流趋势,必将产生海量数据,涉及大型计算和反演,深度学习在地球物理探测中应用将更加广泛.  相似文献   

13.
    
The Sterea Hellas (central Greece) gravity network was remeasured in 1982, with the addition of 40 new stations. There were no statistically significant gravity differences for most of the gravity stations first established in 1968, but four stations—Arta, Preveza, Levadia, and Kymi—exhibited gravity changes of –121, –74, –39, and –67 gal, respectively.In the absence of repeat levelling, the exact amount of vertical displacement cannot be determined. Nevertheless, for Arta and Preveza some theoretical estimates can be made from shallow seismicity data. The vertical displacement deduced from a seismic-moment calculation for the western part of Greece was found to be about 100 mm, corresponding to a slip rate of approximately 7.5 mm/yr. The corresponding gravity change is too small to account fully for that observed at Arta and Preveza. For the rest, other causes, such as creep, should be considered. For the stations Kymi and Levadia the local seismicity is limited, and no calculation was made of the vertical displacement related to earthquakes.Finally, the possibilities in using the central Greece gravity network for studies of earthquake prediction are discussed.  相似文献   

14.
林君  严复雪  皮帅 《地球物理学报》2024,67(12):4433-4455

地球物理仪器是地学仪器的关键分支, 也是地球科学研究的基石, 在资源勘查、环境监测及灾害预防等多个领域扮演着核心角色.由于发展和起步较晚, 我国的高端地球物理仪器长期依赖国外进口, 这严重制约了国产仪器的发展.虽然我国地球物理仪器装备的研发水平近年来取得了进步显著, 但相比发达国家仍存在一定差距.国产仪器应从根本上突破困境, 摆脱对进口仪器的依赖, 加强自主研发和创新能力.本文重点从重、磁、电、震、核磁及放射性测量六个方面阐述了我国地球物理仪器的发展历史及代表性成果.同时, 简述了人工智能在地学仪器中的应用, 概述了制约我国地球物理仪器装备发展的主要问题, 并提出了未来的发展方向.

  相似文献   

15.
以当代经济竞争为背景,简要回顾了中国固体地球物理学的发展史,分析了中国地球物理学人才资源的现状,在数量上,供大于求,但整体结构偏低;人才断层是客观存在,如果能因势利导、正确决策,非但不会导致学科发展的危机,相反,有利于人才结构的合理调整,进而提出了培养人才的对策.  相似文献   

16.
黑岚沟金矿的综合地球物理研究   总被引:1,自引:0,他引:1  
综合地球物理方法寻找隐伏金矿是一种行之有效的方法。由于各种地球物理方法都是建立在各自的岩石物性基础之上的,如何将各种地球物理方法有效的组合在一起,充分发挥各自的方法优势,逐步缩小勘探靶区,最终达到勘探隐伏金矿的目的一直是勘探地球物理工作者追寻的目标。  相似文献   

17.
    
In a recent editorial Richards (1990) advocated a realist perspective for geomorphology. Scientific realism, defined broadly, is the doctrine that science attempts to generate true knowledge of the observable and unobservable (i.e. non-empirical) aspects of an objective world. Various brands of realism exist; the particular version cited by Richards (1990) has not strongly influenced mainstream philosophy of science. Also, critical rationalism, which Richards (1990) contrasts with realism, fully adopts a realist perspective. In its broadest sense, realism encompasses the entire spectrum of geomorpho-logic research, thus providing a unifying philosophical framework for geomorphology.  相似文献   

18.
    
Reduced major axis analysis is used to describe monthly temperature averages for daily maxima, minima, means and ranges at a sequence of bedrock microenvironments in the alpine zone of the Colorado Front Range. Seven thermistors buried at 1 cm in bedrock provide comparative data on easterly, southerly and westerly aspects, and also upon the impact of snow accumulation (?0.5m to ≥4.0m deep) against an east-facing rock wall. Intersite temperatures commonly differ by less than 5°C and, rarely, by more than 10°C. The freezing intensity of freeze-thaw cycles occurring within the confines of a seasonal snow patch rarely dropped to ?5°C, while at snowfree, vertical faces freezing dropped to ?5°C quite commonly. Comparison with laboratory established criteria for effective freeze-thaw weathering (abundant moisture and freezing to at least ?5°C) suggests that moisture rich microsites lack adequate freezing intensity, while adequately frozen sites lack moisture. Available data suggest that the overlap between freeze-thaw and hydration weathering requires careful re-evaluation.  相似文献   

19.
分形在地貌学中应用的几个问题的分析   总被引:5,自引:0,他引:5  
李锰  朱令人  龙海英 《地震研究》2002,25(2):155-162
就实际地貌分形研究工作中经常遇到的截面约定、自仿射分形局域维与渡越长度、分维的比较以及过渡分形等几个问题进行了分析和探讨,并提出了在应用过程中的注意事项和解决方案。  相似文献   

20.
    
Two approaches to modelling surface erosion are described which can be used to explain the development of geomorphological features. The first approach uses non-linear wave theory and shows how surface gradient discontinuities can arise as the erosion of an initially smooth surface proceeds. For isotropic erosion, surface shapes may be predicted by a simple application of the Huyghens wavefront construction and Snell's law at media boundaries. A second approach uses a computational cellular method. The general shapes predicted by the computer simulations are shown to agree with those determined from the wave approach. The application of the cellular method to problems of geomorphological interest are discussed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号