阿德朗达克-西魁北克地震带地壳三维速度结构成像   总被引：2，自引：0，他引：2       下载免费PDF全文

朱介寿 Chun  KY 《地球物理学报》1991,34(2):161-171,T002

根据在阿德朗达克-西魁北克地震带及其邻近地区的59台短周期数字地震仪记录的直达P波走时观测值,用地震层析成像方法反演了该地区地壳三维速度结构.结果表明,地壳上层（0-5km）在阿德朗达克穹隆山的中南部地区出现正速度异常;第二层（5-10km）及第三层（10-15km）的速度横向变化较小,介质相对比较均匀;第四层（15-25km）出现显著的速度异常,一个是位于地震带中部的正速度异常（+4％）,它与布格重力正异常一致;另一个是位于阿德朗达克穹隆山下的负速度异常（-4％）.结合已有的地质及地球物理资料进行对比,可以认为阿德朗达克是一个正在发展的穹隆上升山,但其热源前锋尚未到达地面的大陆热点.  相似文献   

江西安远热隆基本地质特征及其铀矿远景   总被引：3，自引：0，他引：3  

张万良  刘德长  李子颖  张景波 《矿产与地质》2005,19(2):122-126

江西省安远-寻乌地区位于地幔隆起部位，为一热隆伸展构造区，称安远热隆。在阐述安远热隆基本地质特征和地球物理(化学)场特征的基础上，提出热隆边部火山盆地中铀矿成矿潜力较大，具有进一步勘查的意义。  相似文献   

Volcanoes of the Tibesti massif (Chad,northern Africa)     

Jason L. Permenter  Clive Oppenheimer 《Bulletin of Volcanology》2007,69(6):609-626

The Tibesti massif, one of the most prominent features of the Sahara desert, covers an area of some 100,000 km². Though largely absent from scientific inquiry for several decades, it is one of the world’s major volcanic provinces, and a key example of continental hot spot volcanism. The intense activity of the TVP began as early as the Oligocene, though the major products that mark its surface date from Lower Miocene to Quaternary (Furon (Geology of Africa. Oliver & Boyd, Edinburgh (trans 1963, orig French 1960), pp 1–377, 1963)); Gourgaud and Vincent (J Volcanol Geotherm Res 129:261–290, 2004). We present here a new and consistent analysis of each of the main components of the Tibesti Volcanic Province (TVP), based on examination of multispectral imagery and digital elevation data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Our synthesis of these individual surveys shows that the TVP is made up of several shield volcanoes (up to 80 km diameter) with large-scale calderas, extensive lava plateaux and flow fields, widespread tephra deposits, and a highly varied structural relief. We compare morphometric characteristics of the major TVP structures with other hot spot volcanoes (the Hawaiian Islands, the Galápagos Islands, the Canary and Cape Verdes archipelagos, Jebel Marra (western Sudan), and Martian volcanoes), and consider the implications of differing tectonic setting (continental versus oceanic), the thickness and velocity of the lithosphere, the relative sizes of main volcanic features (e.g. summit calderas, steep slopes at summit regions), and the extent and diversity of volcanic features. These comparisons reveal morphologic similarities between volcanism in the Tibesti, the Galápagos, and Western Sudan but also some distinct features of the TVP. Additionally, we find that a relatively haphazard spatial development of the TVP has occurred, with volcanism initially appearing in the Central TVP and subsequently migrating to both the Eastern and Western TVP regions. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.  相似文献   

福州市温泉区地面沉降监测与沉降规律分析     

黄国烟 《测绘工程》1996,5(3):59-63

应用精密水准测量方法，于１９９３年在温泉区取得三个周期的观测成果，结合以往资料进行综合分析，得出初步结论。并为福州市地下热水开采的控制、预防及减轻因沉降产生的地灾害方面提出有益的建议。  相似文献   

湖南中生代岩浆活动与晚二叠世煤变质特征   总被引：2，自引：0，他引：2  

周春光  龚玉红 《现代地质》1996,10(4):470-477

岩体同位素年龄和空间展布分析表明，中生代岩浆活动受多期活动的深大断裂控制且具有多阶段和多期次演化特征。根据Ｘ 射线衍射分析、包体测温、热液矿点的分布以及煤质参数等特征可以证明，除了深成变质作用外，岩浆热变质作用是该区主要的煤变质作用类型。岩浆热变质作用可进一步划分为区域岩浆热变质作用和接触变质作用。通过对湖南的煤类、岩浆活动、构造特征及地球物理特征的比较，可划分出４个煤变质区，其变质程度自北西向南东逐渐增高，这是中、新生代太平洋板块与欧亚板块长期相互作用的结果  相似文献   

地震活动期小汤山温泉的水文地球化学效应     

王基华  金晓微 《地震研究》1992,15(2):205-209

本文介绍了自1987年5月开始观测以来,小汤山温泉溶解H_2、CH_4及电导率在地震活动期的变化特征,并对小汤山(以下统称为井)的映震能力进行了初步讨论。  相似文献   

Thermal bidirectional gap probability model for row crop canopies and validation   总被引：2，自引：0，他引：2  

阎广建  蒋玲梅  王锦地  陈良富  李小文 《中国科学D辑(英文版)》2003,46(12):1241-1249

Land surface temperature is a key parameter in monitoring the status of crop water stress by remote sensing, and studying the water and energy balance in cropland ecosystem. The component temperatures of crop and soil are especially significant in remote …  相似文献   

两种气象绘图软件的对比及应用          下载免费PDF全文

乔春贵王国安  杨建民 《气象与环境科学》2007,30(B09):159-160

介绍了Surfer8．0和Grads（v1．8L11版本）两个等值线绘制软件的功能，根据不同的业务需要，可采用不同的绘图软件，以提高工作效率。  相似文献   

甘肃礼县盐关井水位短临异常与滇北强震的关系          下载免费PDF全文

姚玉霞  王建荣  田继孝 《地震工程学报》2007,29(2):197-199

在分析了甘肃礼县盐关井水位20多年来的异常变化与邻近地区发生中强地震的对应关系基础上,着重就18年来井水位出现两次较大幅度的负异常与相距1000 km多的云南禄劝1985年6.1级地震和云南大姚2003年6.2级地震的对应关系进行了探讨,认为该井很可能是滇北两个震区强震的“穴位”和灵敏点。  相似文献   

Geothermal resource assessment of the United States     

L. J. Patrick Muffler  Robert L. Christiansen 《Pure and Applied Geophysics》1978,117(1-2):160-171

Geothermal resource assessment is the broadly based appraisal of the quantities of heat that might be extracted from the earth and used economically at some reasonable future time. In the United States, the Geological Survey is responsible for preparing geothermal assessments based on the best available data and interpretations. Updates are required every few years owing to increasing knowledge, enlarging data base, improving technology, and changing economics. Because geothermal understanding is incomplete and rapidly evolving, the USGS complements its assessments with a broad program of geothermal research that includes (1) study of geothermal processes on crustal and local scales, (2) regional evaluations, (3) intensive study of type systems before and during exploitation (4) improvement of exploration techniques, and (5) investigation of geoenvironmental constraints.  相似文献