Time variations in the geophysical fields above a gas field on Sakhalin Island

Results of repeated geophysical observations above the Yuzhno-Lugovskoye gas field (southern Sakhalin) carried out from 2003 to 2006 are considered. It is shown that the gas field is a natural indicator of geodynamic processes occurring in the gas field and beyond it. A complex of methods and observations is offered to estimate the degree of productivity of the objects involved in prospecting drilling. They provide further development of the short-term forecast of seismic events by geophysical methods, because seismic pulses propagating from an external source cause sharp changes of the geophysical fields above the gas-containing structure.     

A weak approximation of stochastic time domain electromagnetic response of a conductive permeable sphere

Time domain electromagnetic (TDEM) response of a conductive permeable sphere is a main topic for good understanding and in developing past studies for detection and discrimination of buried metallic objects. Stochastic differential equation model is a valuable tool for stimulating real experience. In this paper, according to an Itô integral, we have obtained a weak approximation of stochastic TDEM response of permeable and nonpermeable sphere. We have used the deterministic solution of TDEM response of conductive permeable sphere by changing one of the variables that have been obtained from the boundary conditions of problem to random variable. By adding white noise to random variable and using stochastic integral, we have displayed stochastic time domain response of conductive permeable sphere. The Itô integral includes a factor that shows infirmity and intensity of noise which has been simply considered constant. Accordingly, we have showed the effect of noise for magnetic and nonmagnetic spheres. Numerical results from step and impulse response of TDEM have shown that the amount of this factor is different for the two types of spheres.     

复杂地表条件下地球物理场数值模拟方法评述

在将起伏地表、复杂近地表构造以及复杂近地表岩性的任意组合统称为复杂地表的一种广义诠释下，分别对近地表岩层或土层的数学物理模型以及对地震波场、电磁波场、稳定电流场、重力场和磁力场在复杂地表条件下的数值模拟方法进行了分析和评述。结果表明，近地表数学物理模型并不是越复杂越好。实践中，要根据计算量以及所要解决的地质问题综合考虑。目前所用到的诸多数值模拟方法，如有限差分法、有限单元法、广义有限差分法、伪谱法、积分方程法和射线法等各有千秋，只要应用得当都能得到正确的结果。作为非网格法代表的积分方程法在对复杂地表和模型内边界的精确描述方面要优于以有限差分法为代表的网格法，而网格法在对模型的适应程度上要优于非网格法。传统的几何射线法在经过一定的修改和补充后，例如加入自由界面转换系数、采用几何绕射理论和Maslov方法，即可用于解决复杂地表条件下的波场数值模拟问题。对于重力场和磁力场，其在起伏地表条件下的空间换算（转换）问题在实质上也是一种正演问题，可纳入到复杂地表数值模拟的框架内去理解和处理。虽然国内外的研究者在复杂地表数值模拟领域内已经做了大量的工作，但离实际应用还有很大的距离。     

Tectonic elements of the Arctic region inferred from small-scale geophysical fields

Satellite altimetry data, Bouguer anomalies, anomalous magnetic field, bottom topography, and Love wave tomography for the deepwater part of the Arctic Ocean Basin and East Siberian Sea have made it possible to detect several new regional tectonic elements. The basin area, 700 km wide and 1800 km long, extending from the Laptev Sea to the Chukchi Borderland is a dextral strike-slip zone with structural elements typical of shearing. The destruction of the Eurasian margin surrounding the Amerasia Basin occurs within this zone. The opening of the Amerasia Basin is characterized by intense plume magmatism superimposed on normal slow spreading in several areas of the paleospreading axis. Magma was supplied through three conduits with minor offsets, the activity of which waned partly or completely by the end of basin formation. The main central conduit formed the structure of the Alpha Ridge. The dextral strike-slip system, which displaces the Gakkel Ridge and structural elements in the basement of the Makarov Basin, most likely extends to the northern termination of the Chukchi Borderland.     

湘南桂北地区地球物理场与铀成矿条件的分析

通过研究湘南桂北地区地质，物探资料，对该地区铀成矿条件进行了分析，认为当前主要在我国北方寻找可地浸砂岩型铀矿床的同时，兼顾在南方寻找花岗岩型铀矿床的工作仍应受到重视。     

Periodicity of geophysical fields and seismicity: possible links with core motion

Years-long data series of Earth’s natural pulse electromagnetic fields (EPEMF) from the Talaya station near Lake Baikal indicates their mainly terrestrial origin and includes a component of poorly understood stable diurnal and annual crustal rhythms. The short-period crustal motion may drive mechanic-to-electric conversion in rocks and be responsible for diurnal and annual VLF electromagnetic pulses.The lithospheric rather than atmospheric origin of many recorded EPEMF signals is supported by their links with nucleation of earthquakes and respective perfect match of the EPEMF and seismicity diurnal patterns. Joint spectral analysis of the Talaya EPEMF and seismicity time series and comparison with the known spectra of lunar and solar tides shows no direct correlation between the short-period rhythms and the gravitation effects.We suggest that the diurnal and annual EPEMF periodicity may be associated with differential motion of the core and lithosphere and use this hypothesis to model an annual core path. As the model predicts, the inner solid core is never at the Earth’s geometric center but moves relative to the latter along a closed orbit; the plane of the core orbit is normal to the equatorial plane and tilted 45° to the direction to the Sun and to the Earth’s orbit; the core rotates 1.1 deg/yr faster than the Earth. The suggested model of core motion is consistent with the known instability of Earth rotation.     

山东夏甸地区金矿床地球物理场特征

山东胶东地区是我国著名的黄金产地,深部含金破碎带与地球物理重磁场有着密切的关系,通过建立以重磁信息为主体的综合找矿标志,可进一步缩小找矿靶区。本次研究以夏甸地区典型金矿床为例,根据布格重力异常图、剩余重力异常图、ΔT化极异常图,讨论了其重磁场特征,结合已知地质剖面和CSAMT剖面解释结果,从重、磁、电三方面论证了本区金矿床具有"低密度、低磁性、低电阻"的物性特点。总结了本区金矿床成矿条件,建立了地质-地球物理模型,在此基础上探讨了一套金矿勘查物探技术组合流程:根据重磁面积工作圈定有利成矿区范围,然后布设重磁剖面,利用其联合反演结果,确定控矿构造的位置及产状,最后根据CSAMT测量结果低阻区(带)的位置可进一步推断矿体位置。该套组合对招远-平度断裂带深部隐伏金矿找矿工作具有重要的指导意义。     

内蒙古达斯呼都格矿区综合地球物理场特征与找矿预测

内蒙古达斯呼都格矿区位于得尔布干成矿带西南段,区内成矿条件优越,成矿类型以斑岩型矿床为主,但工作区内地表草原覆盖严重,几乎没有基岩露头,传统地质手段难以奏效。本文通过地面高精度磁测、大功率激电扫面、音频大地电磁测深等综合物探方法,结合遥感、钻孔等资料,推测了该地区火山机构位置与岩体分布特征以及浅部铅锌矿的分布规律。音频大地电磁测深资料表明,本区岩体可分为两期,其中晚期岩体与成矿关系密切,为下一步矿产勘查指明了方向。     

吐哈盆地十红滩地区区域地球物理场特征及其应用

对研究区已有的物化探资料进行了重新整理、分析解释 ,结合可地浸砂岩型铀成矿理论和已知的控矿地质因素 ,研究和认识十红滩地区地球物理和地球化学场的区域特征 ,在此基础上 ,划分了控矿次级构造单元 ,研究氧化还原带定位 ,确定了地震地层层序 ,分析了铀源及铀的活化迁移等 ,提出了新的认识和见解     

工程物探在某住宅小区规划中的应用效果

工程物探是一种高效、经济的勘察手段，辅以少量的钻探工作可以解决大量的工程勘察实际问题。本文以某住宅小区在规划勘察阶段采用工程物探勘查隐伏构造。论述了小区地质概况及浅层地震、电法勘察的物理前提，说明测线布置及工作方法对结果辅以钻槽探验证资料为修改小区住宅规划布置提供依据。     

Toroidal oscillations of a transradially isotropic elastic sphere

In order to consider the effect of anisotropy on the periods of the oscillations of the Earth, the problem of toroidal oscillations of a transradially isotropic elastic sphere is considered. At each point, the medium is assumed to be transversely isotropic about the radius through the point. The roots of the frequency equation are obtained for different values of the anisotropy parameter α. It is found that, for large order oscillations, the percentage change in the frequency of the toroidal oscillations on account of the anisotropy is nearly equal to |α-1| × 100.     

Analysis of prospecting polymetallic metallogenic belts by comprehensive geophysical method

This paper is based on the analysis and research on the silver-lead-zinc polymetallic ore in New Ballyhoo Banner in southern Manzhouli of Inner Mongolia. Because metal mineralization brings rock formations,the geophysical features such as low resistivity, high polarization rate and uneven distribution of magnetization, the comprehensive geophysical methods are adopted including high-precision magnetic measurement, high-power induced polarization, IP field middle gradient and controlled source audio-frequency magnetotellurics. In the survey work of multi-metal ore deposits, from surface sweeping to single point measurement, and from single point to section going deeper layer by layer, the resolution of measurement is continuously improved, and various geophysical methods support and complement each other, so explorers can successfully predict the direction, scale and volume of the metallogenic belts in conjunction with geochemical exploration, geological survey and drilling. It has provided a strong basis for completing the exploration task of predicting the reserve volume of ore bodies. The research conclusions of this exploration case have thus a high reference value in the same type of exploration work.     

Analysis of prospecting polymetallic metallogenic belts by comprehensive geophysical method

This paper is based on the analysis and research on the silver-lead-zinc polymetallic ore in New Ballyhoo Banner in southern Manzhouli of Inner Mongolia.Because metal mineralization brings rock formations,the geophysical features such as low resistivity,high polarization rate and uneven distribution of magnetization,the comprehensive geophysical methods are adopted including high-precision magnetic measurement,high-power induced polarization,IP field middle gradient and controlled source audio-frequency magnetotellurics.In the survey work of multi-metal ore deposits,from surface sweeping to single point measurement,and from single point to section going deeper layer by layer,the resolution of measurement is continuously improved,and various geophysical methods support and complement each other,so explorers can successfully predict the direction,scale and volume of the metallogenic belts in conjunction with geochemical exploration,geological survey and drilling.It has provided a strong basis for completing the exploration task of predicting the reserve volume of ore bodies.The research conclusions of this exploration case have thus a high reference value in the same type of exploration work.     

关于地球物理勘探数据压缩算法的研究

本文在系统分析目前地球物理勘探中常用的地震勘探技术的特点及产生的数据量庞大性，采集处理时间烦长性等问题，并针对该类问题提出了一种使用的压缩算法，且以通过实际实验结果确认该算法的可行性。     

氢化物无色散原子荧光法测定化探样品中的锡

将样品放入坩埚中用王水溶解,再放入高氯酸,然后在中温电热板加热坩埚至冒高氯酸的白烟,此时硝酸已蒸发掉,趁热加入盐酸将锡还原成低价。用硫脲—抗坏血酸消除铁等过渡金属元素的干扰,用氢化物原子荧光法测定化探样品中的锡。经国家一级标准样品验证,这种方法简便可靠,具有较高的灵敏度和较低的检出限。