Some statistical properties of certain geophysical transport equations

Summary A previously noted analogy between certain transport equations and the heat conductivity equation is further analyzed. It is shown thatPrigogine's nonequilibrium formalism can be directly applied to statistical processes where there is a non-negative constant of the motion. If the total mass (of contaminant, tracer etc.) contained in a fluctuating system is taken as such a constant of the motion, a statistical theory of the corresponding transport process is obtained.     

Techniques for statistical analysis and prediction of geophysical fluid systems

Abstract

Application of statistical estimators to analysis and prediction is examined from the point of view of geophysical fluid dynamics. The fundamental difficulty is that estimators constructed from observational records of limited length (the usual case in GFD) are sensitive to sampling errors in the statistics upon which they are based. To achieve meaningful results, the number of data, or input, parameters must be limited. The relationship between statistical and dynamical models (particularly clear for linear systems) coupled with certain statistical methods are explored with respect to the problem of input parameter selection, both for linear and nonlinear systems. Methods of assessing the effects of sampling errors in hindcasts are discussed and techniques for minimizing these effects in forecasts are evaluated. A method of efficiently condensing statistical models to a few input parameters and transfer functions is given. Finally the steps of hindcast analysis and forecaster construction are discussed from the practical point of view.     

南京地区地球物理场与地震构造稳定性

岩石圈的不均衡状态是地球物理场存在差异的原因,对区域地球物理场进行分析,可以了解岩石圈的不均衡及其构造活动的背景.本文在对南京地区地震地质环境分析的基础上,通过重力异常、地热场、深部速度结构、天然地震层析成像等地球物理资料进行系统分析,研究它们与本区地震构造稳定性的关系;分析研究地震活动,从现今地壳运动速度场与地壳形变...     

发展技术,增强基础-地球物理仪器国际化与地球物理技术在工程上的应用研讨会综述

2004年,中国地球物理学会仪器专业委员会在北京召开了“地球物理仪器国际化问题”(4月)和“地球物理技术在工程上的应用”(8月)两个研讨会。会议发表了大量论文,展示了目前我国先进的地球物理仪器和地球物理技术在工程方面的应用成就．承《地球物理学进展》编辑部支持,决定在2004年第四期和2005年第一期,连续刊载经专家审查和推荐的地球物理仪器和技术方面的部分优秀论文,     

Bounds on the complex conductivity of geophysical mixtures

Following previous work on bounds for complex dielectrics, bounds on the complex conductivity of a mixture of two isotropic components can be developed which are independent of any special assumption concerning the geometry of the mixture. If certain broad restrictions are assumed, such as isotropy of the mixture, then the bounds can be made more restrictive. These bounds reveal the range of the induced polarization response which can be caused by a mixture of two materials of known complex conductivity. The bounds can also be generalized for spectral responses. The bounds are conservative lithologically in the sense that many of the special models corresponding to boundary responses have lithological counterparts. The chief use for the given bounds is to gain insight into the nature of the induced polarization response. It is also possible to use the bounds to estimate the volume fractions of the components. We illustrate how this is done for the case of a general anisotropic medium.     

对廖家湾地球物理异常的新认识

为查明黄沙坪-廖家湾矿集区深部地球物理异常与成矿的关系,以及地下精细结构,本文采用人工地震、AMT、高精度磁测、综合物性研究等探测技术,结合该区的地质资料和前人的物性成果,通过磁、电、震联合反演,探讨了廖家湾成矿地球物理异常的深部地质成因;采用深、浅不同深度的地震反演速度剖面所提供的相对精细、精确的地下介质几何结构与速度变化特征,约束磁性与电性异常的解释,获得了较好的磁-震、电-震的一致性.研究表明:高磁性的矽卡岩与地面和航空磁异常密切相关,成矿地球物理异常与区内多金属矿(化)关系密切,是由深部隐伏钨锡矿(化)矽卡岩体引起.     

基于褶积模型的地球物理反演模型增强

地球物理数据在采集和处理过程中,由于存在噪声、模型误差、以及数据离散化误差等系统误差,导致了异常体边界模糊和模型分辨率降低等一些不可避免的不良系统退化效应的产生.本文提出了一种新的地球物理反演模型增强方法,通过消除反演估计模型中的系统误差,压制模型中的不良系统退化效应,增强反演模型的分辨率.文章从理论上分析了数据中存在的系统误差对模型求解的影响,提出了一个新的系统误差褶积退化模型,并根据该模型提出了一种基于混合范数总变分正则化的盲反褶积模型增强算法.最后,文章通过1D线性反演增强试验和2D大地电磁反演增强试验,验证了所提出的地球物理系统退化模型的正确性,以及盲反褶积增强算法的有效性.试验结果表明,方法可以有效地提高反演参数模型的分辨率.     

野外实验场地球物理电磁数据采集与分析

地球物理电磁数据观测实验场的建立在国内仍属空白,根据开展电磁法的方法技术要求,我们率先选择具备条件的已知矿区作为实验场地,开展了包括国内、外多种型号电磁法仪器(GDP 32Ⅱ、V8、DEM-V、DJS-8A)的相同装置下的同剖面同点位对比试验.对野外实验场上所开展的不同方法每种仪器的数据采集方式与取得结果进行比较分析,并与地质资料进行了结合分析;通过地球物理电磁数据的综合观测研究,形成标准化的数据,将对电磁法仪器开发、仪器引进提供实验检测场地与标准的检测数据,促进地球物理电磁探测技术的研究与发展.     

Geological and geophysical investigations on Deccan Traps

Volcanic rocks occupy considerable regions in the western portion of India, attaining a maximum thickness of 7000′ near Igatpuri. These rocks are essentially basaltic in nature and are generally referred to as plateau basalts. An attempt has been made in this paper to present some results of geological and geophysical investigations carried out in the Deccan Traps. Three areas (Ajanta - Long. 75″41′ -75° 45′ E, Lat. 20° 32′ - 20° 35′ 15″ N, 18 sq. miles in area; Ellora -Long. 75″ 11′ - 75° 16′ E, Lat. 20° 1′ - 20° 9′ N, 80 sq. miles in area; and Chincholi - Long. 77° 22′ - 77° 30′ E, Lat. 17° 22′ -17° 30′ N, 50 sq. miles in area) have been chosen for this study because of their geological setting. A large number of field specimens have been collected for petrographic study. This is supplemented by examination of microsections and chemical analyses of a few traps. In the Chincholi area where the trap overlies the granites, limestones seem to intervene in between trap and granites. With a view to estimate the possible thickness of the limestone beds, the distribution of intensity of magnetic field in a portion of the area has been studied with a magnetometer. Magnetic susceptibilities in case of few specimens have also been studied. Elastic constants of Deccan Traps have been determined for fifty specimens, employing the Wedge Method. These are further correlated with textural features and porosity values. Such an integrated geological and geophysical investigation on Deccan Traps is bound to reveal some interesting results.     

地下地质灾害地球物理探测研究进展

介绍了地下地质灾害地球物理探测方法的基本原理及其研究进展,指出目前常用方法的基本思路及其在实际应用中存在的主要问题,针对观测方法、观测系统、正反演模拟和室内试验研究等方面提出了大胆的构想和新的思路。     

世界物探技术现状及中国物探技术发展的思考

呼图壁地区深层目标合层系白垩系清水河组与侏罗系喀拉扎组、头屯河组（K1q、J3k、J2t）具有规模储层且油气资源丰富,但传统孔隙介质岩石物理建模无法有效区分油气甜点与泥岩。本文在系统分析目标段测井曲线特征基础上,通过微分等效介质岩石物理模型进行横波速度校正,通过Gassman方程流体置换恢复纵横波速度比和纵波阻抗曲线原状地层响应特征,突出甜点储层与泥岩区分度;引入线性滑动理论,建立双孔介质裂缝型储层岩石物理模型。将原生孔隙的微分等效介质岩石物理模型与各向异性次生裂缝的线性滑动模型进行有机融合,实现呼1井-呼6井区孔缝型储层各向异性介质岩石物理建模,构建岩石物理量板。结合叠前OVT域地震数据各向异性反演,有效进行叠前AVAZ裂缝预测。本文形成一套完整的深层甜点预测方法技术流程,为类似探区深层目标勘探开发提供参考。

     

A geophysical interpretation of the 1883 Krakatau eruption

From the present submarine topography in the vicinity of the Krakatau Islands it is concluded that the focus of the large explosions was situated to the northwest of the present Rakata Island. The channel between Krakatau and Sebesi Islands was completely blocked by banks of volcanic material immediately after the eruptions, and it is suggested that this material was mainly lithic fragments.The explosion sequences of Krakatau are deduced from the records of sea-waves and air-waves observed at Jakarta. The large tsunami was caused by the most violent explosion, simultaneously with the largest air-waves. It is inferred that the origin of the tsunami was a sudden upheaval of the seawater due to a violent explosion and that the height of the tsunami near its source was 30–40 m. Energy of the explosion is estimated from analyses of the air-waves as one order of magnitude greater than that of the 1956 Bezymianny eruption; thus, the 1883 Krakatau eruption may have caused explosive removal of more than 10 km³ of material.The subsurface structure of Krakatau Islands after the 1883 eruption is deduced from gravity anomalies. It is concluded that at the bottom of the caldera there are deposits of low density in the shape of an inverted cone 8 km in diameter and 1 km in depth. From the residual gravity anomaly observed over the caldera, one can estimate the mass deficiency there. This allows estimates to be made as to the amount of ejecta. Although large uncertainties remain, these data indicate that explosive removal of material was the main process responsible for the disappearance of the northern half of the former Rakata (Krakatau) Island in the 1883 eruption.     

地质找矿过程中如何提高物探工作质量

本文从六个方面讨论了在地质找矿工作中如何提高物探工作质量，更好地发挥物探作用.这些问题均为作者在多年野外工作中遇到后加以总结.这六方面内容为：测网敷设，物探数据的观测及室内整理，资料成图，岩矿石标本的物性测定，物探工作方法选择，成果解释.     

On the basic principles of geophysical radioactive measurements

Summary The process of radon diffusion in space and time through rocks is treated in detail from the point of view of radiometric prospecting for oil. Taking into account the depth and diffusivity conditions encountered in nature it is stated that vertical radon diffusion reaching from the oil deposits up to the surface cannot be expected. Time intervals as required for setting in of a stationary concentration state and decay conditions of the radon lead to the conclusion that the penetration of emanometric measurements seldom exceeds the depth of 5–10 m.