Electrical Characteristics of Tangjiawan Landslide in Lixian, Sichuan

A wide range of terrain features and landforms,which are exemplified by intricate geological formations and diverse rock compositions,are found in the western mountainous regions of China.These areas frequently encounter geological disasters.As one of the natural disasters,landslides lead to considerable loss of human life and property.Considering mitigation of the losses caused by landslide disasters,a necessary measure for disaster prevention and mitigation involves conducting detailed investigations and monitoring of landslides,which is also the cornerstone of landslide warning.This study compares and analyzes the feasibility of the magnetotelluric detection method for landslides using the results of engineering geological surveys and landslide monitoring.The study aims to address the scientific problem of the validity of using magnetotelluric methods to detect landslide development processes.The Tangjiawan landslide signal on the left side of the K94+000~K94+145 section of the Wenma Expressway is analyzed by employing engineering geological survey,magnetotelluric detection,landslide monitoring,landslide analysis,and other methods.Analysis results provide the static electrical characteristics of lithology,structure,and groundwater,as well as the dynamic electrical characteristics of landslide development.This study focuses on analyzing the relationship between the methods of magnetotelluric detection and engineering geological surveys and the results of landslide monitoring.The workflow and methods for data collection,processing,inversion,interpretation,and analysis using the magnetotelluric method to detect the dynamic development process of landslides are presented in the conclusion.Preliminary conclusions indicate a strong correlation between the dynamic changes in magnetotelluric wave impedance with the surface displacement of landslides and the dynamic changes in groundwater.The use of the magnetotelluric method for landslide detection and monitoring is a feasible example.The research results can offer certain technical references for the detection and monitoring of landslides using magnetotelluric methods and also provide references and guidance for the selection of diversified landslide monitoring methods in the future.

Application of integrated geophysical techniques in geothermal exploration in Binhai County, Jiangsu Province

Integrated geophysical technology is a necessary and effective means for geothermal exploration.However,integration of geophysical technology for large‐scale surveys with those for geothermal reservoir localization is still in development.This study used the controlled source audio‐frequency magnetotelluric method technology for large‐scale exploration to obtain underground electrical structure information and micromotion detection technology to obtain underground wave velocity structure information.The combination of two detection technologies was used for local identification of geothermal reservoirs.Further,auxiliary correction and inversion constraint were implemented through the audio magnetotelluric sounding technology for maximum authenticity restoration of the near‐and transition‐field data.Through these technology improvements,a geothermal geological model was established for the Binhai County of Jiangsu Province in China and potential geothermal well locations were identified.On this basis,a geothermal well was drilled nearly 3000m deep,with a daily water volume of over 2000m3/day and a geothermal water temperature of 51°C at the well head.It is found that predictions using the above integrated geophysical exploration technology are in good agreement with the well geological formation data.This integrated geophysical technology can be effectively applied for geothermal exploration with high precision and reliability.

Integrating Geochemical and Geophysical Method in Coexistence of Oil and Potassium to Identify K-rich Brine:Research and Application in Southwestern Sichuan

Lithology of Triassic in southwestern Sichuan is consistent with the whole basin,and there is no discussion about stratum division,the difference is stratum denudation which is made by the uplifting of Luzhou uplift,especially

Identification methods of coal-bearing source rocks for Yacheng Formation in the western deepwater area of South China Sea

Owing to the fact that the coal-beds are with the characteristics of multi-beds, thin single-bed, rapid lateral changes and deep burial, coal-bearing source rocks are difficult to be identified and predicted, especially in the lower exploration deepwater area. In this paper, a new integrative process utilizing geology and geophysics is proposed for better predicting the distribution of coal-bearing source rocks. Coal-beds were identified by the logging responses of“three higher, three lower, and one expand”and carbargilite were recognized by the characteristics of“four higher and one lower”. Based on the above logical decision, coal-beds and carbargilite can be distinguished automatically by cluster analysis of logging curves in verticality. Within the constraints of well-seismic calibration, the coal-beds group also can be detected in horizontality by the integrated representation of“negative phase, higher Q, lower impedance and lower frequency”within the seismic data. However, the distribution of coal-bearing source rocks utilizing geophysical methodology may do not conform to the geological rules of coal accumulation. And then the main geological controlling factors of coal accumulation are comprehensively analyzed as follows：（1） Paleotopography and tectonic subsidence determine the planar range of terrestrial-marine transitional facies markedly;（2） The relative sea level changes affect the accommodation space and shoreline migration, and limit the vertical range of coal-beds. More specifically, the relationship between the accommodation creation rate and the peat accumulation rate is a fundamental control on coal accumulation. The thickest and most widespread coals form where those two factors reached a state of balance;（3） The supply of autochthonous clasts and the distance between deposition places and paleovegetation accumulated area are the critical factor to form abundant coal, which means that if deposition area is close to paleouplift, there would be sufficient organic matters to form abundant source rocks. The results show that the integrated methods can significantly improve prediction accuracy of coal-bearing source rocks, which is suitable for early exploration of western deepwater area of South China Sea.

Features of Geophysical Fields and Geodynamics of the China Sea

During 1960—1990, an extensive geological-geophysical investigation was carried out in the marine areas of China. According to the materials obtained, the 'Geological—Geophysical Serial Maps of the China Seas and the Adjacent Areas (1:2,000,000)' was compiled. In fact, it is a systematic summary of the geological and geophysical work of the China Seas in the past 30 years.In this paper, the author explains the guiding thought and methodology of the compilation of the serial maps, and then briefly discusses the characteristics of geophysical fields and geodynamics, stratigraphy, tectonics and magmatism.

Four Color Theorem and Applied Geophysics

A selection of a number of geophysical methods to solve different geological, geodynamical, environmental, archaeological and other problems usually has no theoretical substantiation. The solution to this “four color” mathematical problem is able to assume that two independent geophysical methods are sufficient theoretically to characterize the geological-geophysical peculiarities of the area under study.

Application of integrated geophysical interpretation on accumulation body

Integrated geophysical interpretation is a method of combinating different geophysics prospecting methods based on different physical properties of accumulation. As different geophysical methods own different interpretations and varying detection accuracies, the key issue becomes how to integrate the results of several geophysical methods to corrently carry out a comprehensive explanation. Based on different geophysical results, the authors proposed an integrated geophysical explanation method and successfully applied it in practical engineering problems.

Magnetotelluric study of the Xuefeng mountain area,Hu'nan Province,China

A magnetotelluric study was carried out in the Xuefeng mountain uplift belt and its western margins. A detailed investigation was made of the resistivity of the formations, and reliable data were obtained. The sedimentary cover and basement structure of the Xuefeng mountain area and the deep geological structure were analyzed in detail using magnetotelluric data from the twodimensional inversion of the resistivity profile data in combination with regional gravity and magnetic data. It was concluded that the tectonic movements were characterized by basement detachment, and north-south ramp.The study area can be divided into a southern uplift zone, a southern thrust-faulted zone, a central uplift zone, and a northern depression zone. This work has provided geophysical evidence that can be used in future studies of the tectonics and petroleum geology of this region.

坦桑尼亚恩泽加地区覆盖区选区评价及综合找矿方法研究

恩泽加(Nzega)绿岩带为坦桑尼亚环维多利亚湖八大绿岩带之一,为坦桑尼亚重要的产金区域之一。由于其地表覆盖程度较高,地质调查和勘查工作程度较低,虽然针对隐伏型金矿床尚具备一定的找矿潜力,但同时也面临选区评价和找矿困难的问题。研究表明:在选区评价中,针对太古界尼安萨群条带状铁建造的区域航磁异常解译和研究区地球化学金异常分析是最主要的;而在采用地物化综合找矿方法开展勘查工作中,磁法和激电法结合对于寻找覆盖区下的含铁建造内部或接触带附近或剪切带内的金矿床效果较好。该地区首次使用了取样钻施工采样,对覆盖层下发育的含金矿化蚀变带进行了地质工程揭露,取得了一定的找矿成果,先后发现了伊博罗格罗(Iborogo)、卢素(Lusu)和乔马(Choma)等多个金矿床(点)。

垂直电性源瞬变电磁监测在典型地质构造中的应用

矿井地层中存在的地质构造易引起地质灾害的发生,对矿井安全生产造成极大威胁。为提高瞬变电磁法探测精度与探测范围,以电磁场扩散理论为基础,运用正演模拟方法,分析了垂直电性源瞬变电磁场的响应曲线衰减规律,设计了矿井地质构造致灾区垂直电性源在线监测系统,并模拟了垂直电性源TEM对典型断层地质构造的识别能力。结果表明:当发射源长度为1 000 m时,可监测的偏移距离在500~4 500 m,监测深度可达2 000 m,可以满足地质构造的探测需求。感应电动势与电场的六分量在平面图中均可对断层地质构造进行有效识别,其中z方向分量的识别效果最好。在衰减曲线图中,dBx/t与dBy/t对于断层的识别能力较弱,而其余的四个分量均可对断层构造进行有效识别。

物探电磁法在银山脚地区找矿中的应用

为了探明银山脚地区地下隐伏铅锌矿体产状,便于布置钻孔位,对矿体进行物探激电法、高精度磁法测量。物探激电法圈定11个激电异常,高精度磁法圈定1个异常。运用钻孔验证,结合区域岩矿石电磁特性证实,物探激电法在杨柳岗地层中找铅锌矿应考虑地层岩性;高精度磁法测量可作为杨柳岗组炭质灰岩、页岩中寻找铅锌银多金属矿产的方法。钻探与高精度磁法测量在研究区找矿效果明显,并指示出该区的找矿潜力方向。

地质找矿勘查中的物化探方法应用研究

本文深入分析了物化探技术在地质找矿勘查中的应用,结合物理勘探与化学勘探的多种方法以提高勘查精度和效率。通过使用重力、磁性和化学分析等手段,本文旨在减少传统勘查误差,精确预测矿产资源分布,并尽量减少环境干扰。研究结果表明,这些技术的综合应用显著提升了难以接触地区的找矿成功率,同时揭示了现代化勘查技术对专业人才的需求以及未来技术和方法的持续改进的必要性。这不仅提高了勘查技术的实用性,也推动了地质勘查技术的进步和发展。

综合技术在坝址区重大工程地质问题勘察中的应用

针对拟建水库坝址区近坝库岸稳定性问题、坝基抗滑稳定性问题、坝基(肩)渗漏问题,采用工程地质测绘、综合物探、工程地质钻探及坑探、综合试验、综合分析等方法对拟建场地进行勘察,并对主要工程地质问题进行评价。结果表明,采用工程地质钻探与坑探、现场及室内试验、理正边坡稳定性分析的综合方法查明了崩积体的分布情况、组成结构,分析了其形成机理及破坏机制;采用工程地质测绘及赤平投影方法查明了卸荷裂隙的发育情况并分析其对边坡稳定性的影响;采用工程地质钻探、综合物探、压水试验、钻孔电视成像等综合技术查明坝址断层及缓倾角结构面的发育情况及工程性质,评价其对坝基抗滑稳定的影响,勘察效果良好。

综合物探方法在高寒高海拔地区隧道不良地质体勘查中的应用研究——以玛沁隧道为例

隧道地质工程勘察中对地下岩体的破碎和隐伏断裂勘探是一项必要的工作手段。玛沁地区属典型的高寒高海拔地区,单一物探方法因存在多解性而不能较准确地表征勘查区的不良地质体发育情况。为查明玛沁隧道浅地表强分化层的厚度、隐伏断层位置及影响带、破碎软弱带及岩体完整性等不良地质体的分布情况,应用音频大地电磁法和高密度电阻率法等综合物探方法对玛沁隧道发育的不良地质体进行勘探。综合勘查区地质特征和综合物探研究成果表明,综合物探方法在高寒高海拔地区隧道勘查中不仅能够有效识别浅地表强分化层和破碎软弱带等不良地质体,而且可提高物探解释的精度。

斑岩型铜矿勘查中综合物探法的应用研究

在金属矿的不断开发中,地表易识别的矿物逐渐减少,需要加强各类勘查技术的应用,提高找矿效率及精度。单一物探法在勘查中存在一定的不足。以A矿区的勘探为例,研究综合物探法的应用。基于对矿区地质特征的了解,选择重力法、磁法、电法等物探方法进行综合应用,然后进行实际勘查及数据分析。最后,在对物探异常找矿效果进行探讨后,又进行了多参数综合分析、互相补充及互相验证。证实综合物探法能降低物探勘查的多解性,提高地质解释的可信度,实现对斑岩型铜矿的有效勘查。

超前地质预报技术在隧道施工中的组合及应用

在复杂地质条件下的隧道施工过程中,富水构造、断层破碎带及蚀变带等不良地质不仅制约了隧道正常施工,且在不同程度上影响着隧道的施工安全。本文选用“地质调查法+TSP+瞬变电磁法(Transient Electromagnetic Method,TEM)+地质雷达法+超前钻探”综合地质预报方法对侵入岩地区的某隧道开展综合地质预报,分析了掌子面工程地质与水文地质条件,为该隧道前方掌子面安全施工提供了可靠的地质资料支撑,具有十分重要的现实意义。

综合地球物理方法在活断层探测中的应用研究

提出活断层探测综合地球物理方法为遥感、地震勘探、高密度电法、放射性测量,对新乡-商丘断裂(东段)进行了探测,探测结果:研究区第四系覆盖层厚度约160 m,上断点埋深30 m左右,断距由上到下逐渐加大,所探测的断层最新活动时代为晚更新世(Q3p)。结合本次新乡-商丘断裂东段的探测成果,总结出了一套活断层探测技术方法体系。

综合物探方法在城市地质调查中的应用研究:以湖南省常德市鼎城区隐伏基岩探测为例

为在湖南省典型湖相盆地城市低阻覆盖区查明隐伏基岩及其空间分布状态,以常德市鼎城区G4线地质调查剖面为例进行了多方法综合试验研究。首先,介绍了研究区内地质、地层、构造等区域特征;其次,在使用高密度电阻率法和可控源音频大地电磁法进行野外探测试验基础上,引进了广域电磁法和微动勘探等新方法、新技术进行综合探测试验研究;最后,利用多方法探测结果推断了隐伏寒武系灰岩、断裂构造和地层垂向分布情况,并在靶区位置上进行了钻探验证,效果良好。本次调查研究表明:广域电磁法相比传统近地表探测方法,具有高抗噪、探测深度大等其他方法无法比拟的优点,是城市地质调查工作中探查基岩、隐伏构造等目标体的有效方法,而对于地表下百米以内的白垩系和第四系粉砂质地层划分,微动勘探具有明显的效果,值得推广。

物探技术应用下浅层水污染地质特征勘探研究

污染物的排放和泄漏会引起水体富营养化、氧气流失以及生物多样性的丧失等现象,影响水生生物的栖息地和生存条件,破坏水体的生态平衡。为此,提出浅层水污染地质特征勘探研究方法。将山东省泰安市作为研究区域,阐述研究区域的概况;采集浅层水样品,分析其富水性,结合水化学三线图和Gibbs图分析浅层水污染的来源以及演化趋势;采用物探技术中的高密度电阻率法,获取研究区域地层的视电阻率,引入反演法,绘制高密度电阻率成像反演图,分析浅层水污染地质特征。经验证,所提方法在地质特征勘探过程中具有较高的勘探精度。

综合物探在水库大坝渗漏隐患检测中的应用

水库大坝渗漏隐患检测是水利工程安全运行及除险加固工作的重要环节,对保障大坝安全运行及下游人民生命财产安全具有重要意义。笔者根据水库大坝物性特征的分析,充分利用直流电法对渗漏通道视电阻率响应特征灵敏的优点,合理选取了充电法及高密度电法对水库大坝进行综合探测,首先利用充电法追索坝体渗漏通道,然后结合高密度电法对每条测线二维纵向剖面进行解析,通过两种方法的相互验证,有效圈定渗漏隐患发育位置及规模,取得了可靠的成果,从而达到由点及线、由线及面的综合探测效果,为水库大坝渗漏通道排查及除险加固提供精确可靠的依据。