Orogenic structure of the Eastern Alps, Europe, from TRANSALP deep seismic reflection profiling     

Ewald Lüschen  Bernd Lammerer  Helmut Gebrande  Karl Millahn  Rinaldo Nicolich  TRANSALP Working Group 《Tectonophysics》2004,388(1-4):85

The TRANSALP Group, comprising of partner institutions from Italy, Austria and Germany, acquired data on a 340 km long deep seismic reflection line crossing the Eastern Alps between Munich and Venice. Although the field work was split into four campaigns, between fall 1998 and summer 2001, the project gathered for the first time a continuous profile across the Alps using consistent field acquisition and data processing parameters. These sections span the orogen itself, at its broadest width, as well as the editor Fred Davey and the two adjacent basins. Vibroseis and explosion data, complementary in their depth penetration and resolution characteristics, were obtained along with wide-angle and teleseismic data. The profile shows a bi-vergent asymmetric structure of the crust beneath the Alpine axis which reaches a maximum thickness of 55 km, and 80–100 km long transcrustal ramps, the southward dipping ‘Sub-Tauern-Ramp’ and the northward-dipping ‘Sub-Dolomites-Ramp’. Strongly reflective patterns of these ramps can be traced towards the north to the Inn Valley and towards the south to the Valsugana thrust belt, both of which show enhanced seismicity in the brittle upper crust. The seismic sections do not reveal any direct evidence for the presence of the Periadriatic Fault system, the presumed equivalent to the Insubric Line in the Western Alps. According to our new evolutionary model, the Sub-Tauern-Ramp is linked at depth with remnants of the subducted Penninic Ocean. The ‘crocodile’-type model describes an upper/lower crustal decoupling and wedging of both the European and the Adriatic–African continents.  相似文献   

电磁阵列剖面-大地电磁联合测量及其资料处理   总被引：1，自引：0，他引：1       下载免费PDF全文

邓前辉  陈木森 《地震地质》1998,20(3):59-254

电磁阵列剖面（ＥＭＡＰ）与大地电磁（ＭＴ）联合测量是在作ＥＭＡＰ测量的同时获得一个大地电磁测深点的测量结果。其优点是：（１）测量剖面不仅获得ＥＭＡＰ资料,而且还获取完整的ＭＴ资料,增加了测量的信息量;（２）弥补了单纯ＥＭＡＰ测量时深部信息可能不足的缺陷;（３）提供了ＥＭＡＰ与ＭＴ综合研究的最佳资料  相似文献   

The upper ocean circulation at Great Meteor Seamount     

Aike Beckmann  Christian Mohn 《Ocean Dynamics》2002,52(4):179-193

 The circulation patterns at Meteor Seamount are investigated for implications for the marine ecosystem, using a numerical ocean circulation model. The importance of tidal amplification and rectification as well as internal tide generation has been documented in Part I of this study. Passive tracers confirm the idea that there is an area above the seamount which is largely isolated from the surroundings. Lagrangian particle trajectories are used to test and quantify the potential for retention. We find that passively advected organisms are more likely to remain in the near-surface layers above Meteor Seamount than actively migrating organisms, which might escape from the area. Finally, the importance of strong wind events on the distribution of particles is illustrated. Received: 10 January 2002 / Accepted: 2 September 2002 Acknowledgements The authors gratefully acknowledge helpful discussions with Catriona Clemmesen, Rabea Diekmann, Frank Hartmann, Inga Hense, Manfred Kaufmann and Bettina Martin. This work was funded by the DFG under contracts Me 487/38-2 and Be 1851/1-1 as part of the Great Meteor Seamount project. Responsible Editor: Jean-Marie Beckers  相似文献   

Gravity profiling as a technique for determining the thickness of glacier ice     

E. Klingele  H. -G. Kahle 《Pure and Applied Geophysics》1977,115(4):989-998

Summary Detailed gravity measurements recently carried out on the Gorner glacier, Switzerland, are used to determine the variation of thickness across the glacier ice. The Gorner glacier was chosen as a test site because seismic control was available. The glacier ice at a profile near the Monte Rosa massif is associated with a relative gravity low of about –23 mgal. Model oalculations yield a corresponding ice thickness of about 400 m at the central part of the profile. A comparison of the derived residual gravity anomaly with the calculated effect of the 3-D ice model based on seismic information is made. It is shown that the regional field determined for the Gorner glacier is appropriate and gives the correct residual anomaly associated with the glacier ice. Therefore, the proposed gravity technique for determining variations of the thickness of glacier ice appears to be a valuable and rather inexpensive method for surveying glaciers.Institut für Geophysik, ETH-Zürich, Contribution No 145.  相似文献   

Gradient profiling for the investigation of groundwater saturated fractures in hard rocks of Uttar Pradesh,India     

G. S. Yadav  Shashi Kant Singh 《Hydrogeology Journal》2008,16(2):363-372

Gradient profiling (GP) has been successfully utilized as a preliminary tool to identify fractured zones saturated with groundwater in hard-rock areas of Robertsganj, Sonebhadra district, Uttar Pradesh, India. Conducting geoelectrical sounding at randomly selected places may not provide fruitful results since fractures are sparsely distributed in hard rocks. In gradient profiling, current electrodes with large separation remain fixed while the potential dipole is moved between the current electrodes in the central one-third portion of the profile at a small station interval. A GP survey was conducted along seven profiles having different lengths in two small sectors of the study area. Low resistive zones have been identified which correspond to the fractured zones. A few geoelectrical soundings were carried out to investigate the depth and thickness of the fractured zones. Two test boreholes, one drilled in each sector, yielded continuous discharge of fresh water (18,000–24,000 L/h). The present study confirms the findings of previous work that the GP survey is a powerful initial technique that identifies the presence of a fractured zone, especially in a hard-rock area covered with a thin soil layer.  相似文献   

水下DGPS定位系统可定位范围分析   总被引：1，自引：0，他引：1  

朱祥娥  蔡艳辉  王权 《全球定位系统》2008,33(4)

水下DGPS定位系统是我国近些年研制的一套水声定位系统,该系统经过了在三亚、抚仙湖等地区的试验,得到了较高的定位精度.利用Argo浮标剖面数据,将海水视为水平分层均匀介质,计算声速剖面,根据Snell定律从理论上推出了理想情况下水下导航定位系统中浮标的可布设范围和水下DGPS定位系统浮标阵的可定位范围.  相似文献   

国际合作INDEPTH项目横穿青藏高原的深部探测与综合研究   总被引：10，自引：1，他引：9  

赵文津  吴珍汉  史大年  熊嘉育  薛光琦  宿和平  胡道功  叶培盛 《地球学报》2008,29(3):328-342

国际合作青藏高原与喜马拉雅深部剖面探测(INDEPTH)计划自1992年开展以来,圆满完成Ⅰ、Ⅱ、Ⅲ、3个阶段研究任务,揭示了喜马拉雅山和青藏高原腹地的地壳结构和深部构造,在同际核心期刊公开发表10多篇有重要影响的学术论文,受到国际地球科学界的高度评价.第四阶段计划是研究高原北部边缘,即东昆仑造山带和柴达木盆地的结构构造及其形成演化,并与南部喜马拉雅造山带加以对比.经过多次野外地质踏勘,选定剖面的工作路线,2007年各方正式签订协议,并共同开展了野外调查,圆满完成了横穿东昆仑造山带和柴达木盆地的100km垂直深反射地震、300 km广角地震反射以及59个宽频带天然地震台站的野外观测施工任务.中方项目组还在东昆仑南部厘定出渐新世晚期-中新世早期大型逆冲推覆构造系统,发现青藏高原渐新世晚期-中新世早期整体隆升的重要证据.2008年将继续天然地震观测,还将开展大地屯磁测深、重力、地质构造剖面观测和反射地震数据处理;2009～2010年将利用各类深部探测资料,综合研究青藏高原北部的地壳结构、岩石圈构造和深部过程.  相似文献   

综合电法在红层地区地下水勘探中的应用     

梁延广  ;王美岭  ;张彦湘 《中国煤炭地质》2008,(11):69-71

在胶莱盆地,其红层所属地层岩性为粉砂岩、泥岩,含、透水性较差,查找低阻断裂构造是其地下水勘探的唯一途径。而红层地区的压扭性断层,会因挤压密实的断层泥存在,导致单纯利用低电阻率参数判定地下水的赋存位置出现差错。根据该区地下水的自然电位异常值约为-100mV、含水破碎砂岩极化率大于2％、衰减度D大于50％的特点,提出了自然电位观测法与激发极化电测深法相结合的组合方法。即利用自然电场法进行剖面测量,判定含水异常位置,然后利用激发极化电测深法准确判定地下水所在层位及埋深。在胶州市某镇政府水源勘探中,利用该组合方法,成功的圈定了3个井位,并在预定的深度内打出了单井出水量为1000t／d的优质井。  相似文献   

利用Argo浮标资料分析横跨吕宋海峡20.5°N断面的水文特征   总被引：2，自引：0，他引：2  

黄志达  胡建宇 《台湾海峡》2010,29(4):539-546

基于Argo浮标资料,分析了一条横跨南海北部、吕宋海峡和西太平洋（20.5°N,114°~130°E）断面的海水温度、盐度的分布特征.其结果表明：Argo剖面资料得到的2008年秋季20.5°N断面海水的温度、盐度分布态势与气候态秋季的分布基本一致,主要差异在于南海次表层水的盐度极大值和西太平洋次表层水的盐度极大值,2008年秋季二者均比气候态秋季的低0.1左右.通过动力计算（选取1 200 m为速度零面）表明：Argo浮标剖面资料与融合的卫星高度计产品得到的20.5°N,117.5°~124.5°E断面的表层地转流北分量的分布比较吻合;吕宋海峡中部（20°~21°N）的黑潮主轴大致位于121.5°E附近,其东边界可达123°E,而西边界仅限于121°E以西,其可能原因是该季节黑潮的左侧存在着一个气旋式环流,阻碍了黑潮西进;黑潮在20.5°N断面的体积流量为27×106m3/s左右,最大流速约为55 cm/s,出现在70 m层左右.  相似文献   

Joint interpretation of geoelectrical and volatile organic compounds data: a case study in a hydrocarbons contaminated urban site     

《Geofísica Internacional》2014,53(2):183-198

As a result of a gasoline spill in an urban area, Electrical Resistivity Tomography (ERT), Electromagnetic Profiling (EMP) and Volatile Organic Compounds (VOC) methods were used in order to define the contamination plume and to optimize the drilling and soil sampling activities. The VOC anomalies (recent contamination) indicated that a gas station located at the study site is an active contamination source. The mature contaminated zones defined by ERT and EMP methods corresponded with low resistivity anomalies due to degradation process of the hydrocarbons contaminants. The ERT, EMP and VOC results were integrated on a map, allowing the final configuration of contamination plumes and the optimization of drilling and soil/free-product sampling. Laboratory analyses of free-product samples suggest the existence of more than one contamination event in the site, with the presence of recent and degraded-hydrocarbon contaminants classified in the gasoline range. This study shows the advantages of joint application of ERT, EMP and VOC methods in sites with active contamination source, where the existence of recent and mature contaminants in subsoil is assumed.  相似文献