对反向变分流电法勘探原理的剖析     

Fu Liangkui 《地球科学》1986,(2)

本文阐明了反向变分流系统地下电流的分布特点和规律。文中还给出了反向变分流电阻率法视电阻率的异常表达式,计算了装置系数和电流分配系数之间的关系,并阐明其规律和作用。最后,作为一个例子,分析了水平地层上反向变分流电测深法视电阻率的异常分布规律,并指出它在勘探中的作用。  相似文献   

Anomalous induction across Europe   总被引：1，自引：0，他引：1  

Oldřich Praus  Jana Pěčová 《Studia Geophysica et Geodaetica》1995,39(3):286-288

Summary Using real induction vector data, collected at 958 European observation sites, together with our data from the Bohemian Massif and the West Carpathians, we have generated a contour map of the transfer function TF1 (corresponding to transfer function A in Wiese's relation). Only the zero contour is retained and shown on the map. It clearly marks the main anomalous induction zones, related to internal structural inhomogeneities, across Europe.  相似文献   

Investigation of electrical anisotropy in the deep borehole KTB     

Armin Rauen  Marcela Lastovickova 《Surveys in Geophysics》1995,16(1):37-46

Information about electrical anisotropy in and around the deep borehole of the German Continental Deep Drilling Program (KTB) has been acquired using three different methods: (1) Under surface temperature and pressure conditions, the azimuthal dependence of resistivity has been measured in horizontal planes perpendicular to the axes of drill cores. (2) Simulated in-situ conditions (high temperature and pressure) have been applied to mini cores drilled at different orientations to structural features such as foliation. The resistivity was then measured in the direction of the mini cores' long axes. (3) Under quasi-in-situ (downhole) conditions, the azimuthal dependence of resistivity has been measured in horizontal planes using the Azimuthal Resistivity Imager (ARI), a down hole logging tool.These investigations have shown that electrical anisotropy is strongly related to structural features. The anisotropy of gneisses is the highest due to the strong foliation (averaged anisotropy factor 2.8). Lamprophyres are most isotropic (factor 1.2). Most rocks from KTB are amphibolites with intermediate anisotropies (factor 1.3). The anisotropies measured under surface temperature and pressure conditions and quasi-in-situ conditions on amphibolites are approximately the same, whereas anisotropies under simulated in-situ conditions are partially higher.Furthermore, the anisotropies measured on the cm to m scale using the various methods outlined above shall be compared with large scale anisotropies of the km scale measured around KTB using Magneto Tellurics.  相似文献   

Study　on　electric　variations　of　media　in　epicentral　area　by　geomagnetic　transfer　functions   总被引：1，自引：0，他引：1  

曾小苹  林云芳  朱忠杰  续春荣  赵明  张崇阳  刘绮亮 《地震学报(英文版)》1995,8(3):413-418

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地电前兆异常特征及澜沧—耿马7.6级等地震预报问题     

汪志亮  王志贤 《地震》1995,(3):240-245

深入研究了全国地电台网内M_s≥5.0的45次地电前兆震例,用统计方法按大震、强震、中强地震分别研究其地电前兆特征。 通过研究得到:大震地电阻率异常范围,其半径超过200km,在700km以内,异常时间在12—20个月内发震的概率最高,为97.8％;强震地电阻率异常范围大多在300km以内,趋势异常的时间在12个月以内发震的概率最高,为86.5％;中强地震地电阻率异常范围,半径一般在200km以内,趋势异常时间在180天之内发震的概率最高,为95.0％。大震、强震、中强地震地电趋势异常时间似乎存在着20个月、12个月、6个月三个不同的异常时间段。 临震异常类型一般可分为加速型、转向型和波动型三类。对7级和7级以上大震能观测到临震异常前兆的震例只有33.3％、强震和中强地震能观测到临震异常前兆的震例均为50.0％。出现临震异常后1—20天发震的概率最高,达94.4％。 1988年11月以来,西部地区先后发生澜沧-耿马7.6、巴塘6.7、天祝6.2级地震。震前都曾依据地电前兆短临异常特征,作过某种程度的监测预报工作,取得了较好的短临预报效果。  相似文献   

天水地区大地电磁测量及深部电性结构   总被引：3，自引：0，他引：3       下载免费PDF全文

刘宝勤  朱佐全  贾政  郭万武  李柱国  张文仁  屈健鹏 《地震工程学报》1995,17(4):70-78

天水地区的大地电磁测量结果表明，在４３ｋｍ左右的深度上普遍存在高导层，这可能是壳幔过渡带的反映。岩石圈厚度大约９５－１１０ｋｍ。在天水太京附近可能存在一条大型近东西向地壳－岩石圈构造带，在秦安以北的叶堡和陇城附近可能也存在一条近南北向的大型地壳－岩石圈构造带，它们都是不同构造单元的分界线。１６５４年天水８级大震可能与深部热异常引起的热应力有关。  相似文献   

频率测深波区视电阻率响应和正演计算     

殷长春 《吉林大学学报(地球科学版)》1987,(3)

本文对频率测深电偶源发射时的波区视电阻率响应进行了较系统的讨论,指出了国内现有理论中的一些错误。研究发现,在进行波区视电阻率响应的理论推导时,当基底电阻率有限时进行零级近似是正确的,但当基底电阻率为无限大时,进行零级近似是不完善的,必须进行修改。利用正确的公式进行了视电阻率响应的正演计算,结果表明,利用零级近似得出的公式与利用一级近似得出的公式计算的视电阻率响应曲线首支部分符合较好,但对于有高阻基底存在的地电断面,响应曲线尾支差异很大。  相似文献   

璜山金矿找矿模式及应用     

黄仁荣  何长友 《浙江国土资源》2001,17(2):27-32

诸暨璜山金矿是除治岭头以外浙江省第二金矿,它的找矿模式为"三高两低一复合"的找矿模式,即高金晕、高极化率、高磁场跳跃、低电阻率、低电位和北东断裂与北东东断裂复合处是成矿最有利部位.在其附近仍有类似成矿部位,有望扩大远景.  相似文献   

堤防隐患探测实例分析   总被引：2，自引：0，他引：2  

石念增  刘康和 《地质灾害与环境保护》2005,16(4):376-382

在堤防隐患探测中，采用地质雷达、高密度电法、电测深法、地震折射波法等综合物探技术，并结合少量的土工试验资料，提高了物探成果的可靠性和实用性，取得了良好的应用效果．为堤防隐患探测提供了新的思路。  相似文献   

Morphology and internal structure of a dormant landslide in a hilly area: The Collinabos landslide (Belgium)     

M. Van Den Eeckhaut  G. Verstraeten  J. Poesen 《Geomorphology》2007,89(3-4):258-273

This study attempts to reconstruct the history of the Collinabos landslide, a landslide with a fresh morphology that is representative for more than 150 dormant, deep-seated (> 3 m) landslides in the Flemish Ardennes (Belgium). A geomorphological map was created based on LIDAR (Light Detection and Ranging)-derived maps and detailed field surveys. The map showed that the landslide consisted of three zones with significant differences in surface topography. The northern landslide zone 1 is characterised by at least five reverse slopes, whereas zones 2 and 3, the southern landslide zones, have only two reverse slopes and a convex foot. Electric resistivity profiles measured in zones 1 and 2 revealed that the differences in surface topography were not related to differences in internal structure as both parts of the landslide were initiated as a rotational earth slide with a surface of rupture at 15 m deep, where the displaced material broke apart in two blocks. However, two shear surfaces of reactivations within landslide debris were only distinguished in the accumulation area of zone 1. The observed differences in surface morphology can be caused by a temporary conversion of a forest into cropland in zone 2. It is suggested that reverse slopes of smaller reactivations within landslide debris were obliterated during the agricultural activities. AMS radiocarbon dating of organic material found in ponds located in reverse slopes generally resulted in relatively recent dates (i.e. 1400–1950 Cal AD) suggesting that several of the small local reactivations occurred in that period. One dating at 8700–8440 Cal BP of organic matter collected in a reverse slope in zone 1 suggests that an initiation under periglacial conditions cannot be excluded for the Collinabos landslide. By combining different technologies, this study provides valuable information for a better understanding of dormant landslides.  相似文献