Based on a brief review of the development history and an analysis of the present situation of airborne radioactivity survey technology in China, this paper points out that a complete system of airborne radioactivity survey technology has been formed in China. By making a systematic and comprehensive summary of the major progress and technological innovation achievements of airborne radioactivity survey in China over the past 60 years, the authors believe that the research and development of airborne radioactivity instrument and the technical level have reached the international advanced level, and the technological innovation achievements have been expanded from mineral exploration to engineering geology, hydrogeological survey, environmental investigation, monitoring and some other fields. This paper discusses the main directions of airborne radioactivity survey technology development, summarizes the main problems that are exposed in practical work, and puts forward some suggestions for further work which have a certain guiding significance for uranium exploration based on airborne radioactivity survey as well as for investigation and planning of basic geological and environmental work in China.

The current rapid urbanization and underground development have brought challenges and good opportunities for the development of shallow seismic exploration technology.In this paper,the main advances made in shallow seismic exploration in cities in recent years have been introduced in terms of seismic exploration equipment,data acquisition,data processing,interpretation and their applications,which include the development of seismic land-streamer systems,wireless seismic data acquisition,vibroseis pseudo-random sweeps method,urban noise surface wave exploration technology and comprehensive data processing algorithms.Some conclusions have been reached:the Rayleigh wave constrained refraction P-wave tomography results or the joint inversion method can improve the accuracy of detection of urban underground "100-meter" space;using urban noise as a source,it can not only provide supplementary information that is important for the description of shallow geological features,but also meets the city's requirements for green and environmental protection;through the seismic land-streamer system,S-wave technology can play a more important role in urban shallow exploration.Some proposals for future development are put forward:First,to strengthen the research and development of key technologies and equipment for shallow seismic data acquisition in urban area;Second,to further develop and improve non-traditional (such as surface wave) seismic exploration methods,and to dig deeply into a large amount of useful information contained in seismic waves.

Pre-stack simultaneous inversion is one of the main techniques for reservoir fluid identification,but there are still some uncertainties due to the complexity of underground geology and the multiple ambiguities of geophysical response characteristics.In this paper,on the basis of the fluid substitution,firstly the seismic amplitude response characteristics are analyzed,secondly the sensitive parameter suitable for this area is quantitatively screened through fluid evaluation factors,and finally the fluid indicator profile is obtained by pre-stack simultaneous inversion.The study shows that the high porosity water layer is the key interference factor for fluid identification in this area,and λ/μ parameter is the most suitable fluid identification factor.The practical application shows that the strong amplitude is suppressed effectively at the water layer by the method and the accuracy of fluid identification is improved obviously.

In this study, the molybdenum prospecting target was delineated quickly by 1:10 000 geological mapping and 1:25 000 soil geochemical survey in the drainage system on the basis of optimizing 1:200 000 comprehensive anomaly of Mo-based ore-forming elements. The favorable areas for ore prospecting were delineated on the basis of comprehensive research. And then, the Chagandeersi large molybdenum deposit was discovered by exploratory drilling in Urad Rear Banner, Inner Mongolia. The result has proved that large-scale soil geochemical survey in the drainage system is crucial in search for ore deposits. The geological-geochemical prospecting criteria of this kind of deposits are summarized in this paper, and this provides reference in search for concealed ore deposits.

The Zhuyuangou Mo deposit is a middle-sized Mo deposit newly discovered in the East Qingling-Dabie Mo metalogenic belt. It is a porphyry Mo deposit.Based on an analytic study of the results obtained from the regional geophysical and geochemical exploration,and geochemical exploration of the ore block in the Zhuyuangou Mo-deposit,the authors summarized the geophysical and geochemical prospecting methods for Mo deposits.The results show that geophysical and geochemical methods have played a significant role in prospecting and exploration and, on such a basis, the authors pointed out some areas which deserve attention in prospecting: the distribution of molybdenum-bearing intrusive bodies in the range of low gravity anomaly and low magnetic anomaly;stacking areas of 1:50 000 high temperature hydrothermal mineral placer anomalies and comprehensive geochemical anomalies of stream sediments of elements like Mo, Pb, (Au) ;overlapping areas of different-scale Mo, Pb, (Ag) geochemical anomalies.

In recent years, exploration of gold ore deposits in the Qinba region of Shaanxi Province has become increasingly difficult. Based on the study of gold enrichment patterns and geochemical prospecting models for different types of gold deposits in this area and following the rules of finding the similar deposits with similar geological conditions and similar anomaly characteristics. Starting with the characteristics of Au anomaly distribution, elemental composition and geological background, combined with the current exploration results for gold ore deposits, and based on analysis, comparison, classification and screening of anomalies, the authors divided the Qinba region in Shaanxi Province into 12 gold prospecting areas. The characteristics of geology, geochemistry, ore-controlling conditions, major ore-prone areas and mineral types of each prospecting area were also figured out. In addition, the direction for the prospecting deployment in this region were pointed out for reference.

In view of the special seismic and geological conditions of the Loess Plateau,such as large thickness of loess layer,deep diving and complex terrain,the authors took the LA exploration area in the south of Ordos Basin as an example and used acquisition technology analysis and experiment to summarize the countermeasures suitable for coalfield seismic exploration acquisition technology in the Loess Plateau area.First,the seismic geological conditions of the LA exploration area were analyzed.Then,on the basis of the technical parameters analysis of the curved line construction,the acquisition parameters were tested and analyzed,and the parameters,such as the depth of the well,the amount of charge,the well combination and the spacing between wells,were determined.by using the crook seismic prospecting.Using different excitation methods for different terrains through experiments can overcome shooting and receiving difficulties caused by thick loess,steep ravine,and dry and loosen loess,thus achieving good effect.The result obtained by the authors provides valuable reference for coalfield seismic exploration in loess tableland area.

Mazong Mountain is located in the eastern section of the Beishan gold mining area. Gold deposits are associated with anomalies detected by airborne radioactivity measurements, which are located in uranium anomalous edge gradient belt. By using the radioactivity measurement method, the authors found that the Shibandun uranium anomaly is located in the contact zone between Dundunshan magma mass and Sangejing groups and is controlled by two EW-trending broken quartz veins. The U content is higher than 18 × 10 ^-6 in Shibandun uranium anomaly and exceeds 10 × 10 ^-6 industrial boundary grade standard. Trough revealed that the uranium and gold have association characteristics. Gold content is (0.5 ~ 6.16) × 10 ^-6, and has reached the industrial grade. Therefore the radioactive measurement method is a rapid and effective method in the search for uranium and gold deposits in Mazong Mountain area.

Aerbulage area in Hulunbuir of Inner Mongolia is an area with wide volcanic rock distribution. In order to study the uranium mineralization characteristics, the authors used the ground gamma spectrometry method. Based on the application of ground gamma spectrometry in this area, the authors investigated the distribution characteristics of uranium anomalous mineralization in this area and delineated two favorable uranium metallogenic sections, which indicates that the method has obvious effect in uranium ore prospecting, and has a certain guiding role in the further key verification work.

The ancient wooden wrecks and their stowage, which bear the history of human civilization and progress and have archaeological significance and value, have aroused much interest among archaeologists and historians, and their recovery is very important. Nevertheless, underwater active detection for buried wooden wrecks is similar to the search for a needle in a haystack, and hence no report has been seen up till now. Through a case study of wooden ship detection and validation, the authors confirmed that a high precision magnetic method is not only suitable for detecting a wooden wreck but also can verify the size and plane projection position of the wreck through the interpretation of magnetic anomaly caused by the wreck and thus excavate the valuable information. Practice shows that the magnetic prospecting technique can be used to detect the wooden wreck with reliability and effectiveness.

In this paper,according to the problems existent in spectrum IP and phase IP work,the authors put forward a new method of sine wave phase IP. By using the narrow-band filter based on single frequency sine wave signal,the interference can be attenuated by large db, and phase shift of fixed frequency filter can be compensated. In the case of sinusoidal waveform locking,IP absolute phase can be carved directly and read with single-chip microcomputer counter. The resistivity is calculated by A/D acquisition amplitude positioned at sine wave peak. The sine wave phase IP working frequency is 1Hz~12.5Hz,and it has the advantages of simpleness and quickness,low equipment cost,relatively low electrode grounding requirement,rapid geophysical prospecting measurement,and strong capability of anti-power frequency harassment and anti-stray DC interference. This method is especially suitable for mine geophysical prospecting, which can overcome the disadvantages of current frequency domain IP such as high cost, low efficiency and unsuitability for fault survey. The method expands the new applications in the mine production.

Based on the principle of the response characteristics of different filtering seismic wave fields on different scale fractures,the authors detected and characterized the small scale fractures by identifying the boundary of the amplitude of seismic wave caused by geological body in the vertical and horizontal direction,and combined the theory of multi-scale boundary detection with the characteristics of seismic wave field in the fracture zone of coal measure strata.The method can detect the subtle variation information caused by the small scale fracture,and improve the resolution of the seismic prediction.The prediction and study results coincide with the logging detection and the fracture system regularity in Qinshui Basin area.

Gravity data embody the superimposed effect of all the bodies with uneven densities from the earth surface to the deep subsurface. And gravity data with different scales are needed for different tasks. The two-dimensional empirical mode decomposition can be adapted to nonlinear or non-stationary signals to achieve the multi-scale decomposition. In this study, the authors applied the two-dimensional empirical mode decomposition to the multi-scale analysis of gravity data. With this method, the gravity data can be decomposed into different intrinsic mode functions and one remaining component. Then, the radial logarithmic power spectrum of various components are computed to get the approximate depth of various sources. Theoretical density model data and real data test support the technical feasibility of the method.

The previous methods for the discrimination of groundwater hydrochemical types in karst areas of Xianning, such as the ShuKaliefu's classification, have some shortcomings. In view of such a situation, this paper proposes the systematic cluster analysis method. The four processes of the system clustering method, i.e., matrix construction, similarity degree representation, elimination of dimensional difference and sample system clustering, were discussed in this paper. The corresponding programs were compiled for the systematic cluster method, and the groundwater from the karst area of Xianning was taken as an example. When the threshold is 3.2, the hydrochemical type can be divided into 10 categories. Finally, a comparative analysis of each classification was carried out with Shug Kalev classification, and it is proved that the systematic cluster analysis method is effective.

Due to the violent surface fluctuation and the lateral variation of the low velocity layer,the static correction is the key and difficult part of seismic data processing in such areas.The method of tomographic static correction is widely used in the field of seismic data processing by using the travel time and path of the first arrival wave to build the medium velocity structure,which is not restricted by vertical and horizontal changes of the near surface structure and the surface.This paper gives a brief description of the technology of man-machine interaction and automatic tomography,and describes the realization process of the two technologies.Combined with the actual data of the northern Ordos area,the authors carried out a comparative study of the application effect about seven indicators,i.e.,the first arrival wave picking,inversion model,the static correction,the residual static of reflected wave,the profile,the closed error and the long-wavelength static correction.The differences between the two technologies are explained, which provides the basis for selecting the practical and efficient static correction technologies for seismic data processing.

Severe attenuation by earth absorption and low S/N ratio exists in western China's desert areas.In order to improve the seismic exploration quality of geological targets,the authors put forward a nonlinear sweeping signal design method based on reflection frequency characteristics of target strata to enhance reflection data signal-to-noise ratio of purpose layers.According to characteristics of reflection data frequency spectrum and exploration mission requirements of major purpose layers,the expected frequency spectrum characteristic curves are designed,which are used as distribution relationship between sweeping frequency and energy and applied to controlling the dwell time of sweeping frequency.Then,nonlinear time-frequency relationship is computed and nonlinear sweeping signals are obtained.This method highlights the anticipated dominant frequency energy of sweeping signals and optimizes the seismic wave frequency spectrum of vibrator outputs.Forward modeling and single shot seismic record tests have verified the correctness and validity of this method.Good results are obtained through application tests.

Synthetic seismic record calibration is the basis of structural interpretation and reservoir prediction.The accuracy of synthetic seismic record calibration directly determines the accuracy of subsequent structural interpretation and reservoir prediction,and only when the polarity of the corresponding seismic section is accurately determined,the calibration can be accurate.Therefore,determining the polarity of seismic data is the most basic work.In practical production applications,the conventional method which uses the positive and negative polar waves to produce the synthetic seismic records and then compare the correspondence between the two and the seismic trace often fails to determine the polarity of the seismic profile.In this paper,the polarity determination of the Sulige gas field was taken as an example and,according to the principle of phase scanning,the forward modeling and formula derivation were conducted.The results show that the phase of the seismic profile and phase correction quantities are opposite.In the actual data analysis,the phase correction can be obtained by using the phase scanning to compare the well impedance and the relative impedance of the seismic traces nearby the borehole,and then the phase of the actual seismic profile can be obtained to determine the polarity of the seismic profile.The method is intuitive and has good operation and popularization in practical application.

On the basis of the first-order velocity-stress elastic wave equation,a finite-difference discretization scheme with 2M-order accuracy of second-order space accuracy is deduced based on rotational staggered grid.The principle of recursive convolutional complex frequency shift perfectly matched layer (CPML) boundary condition is expounded,and the recurrence formula of first order velocity-stress elastic wave high order difference CPML boundary condition is established.The selection of the key parameter m,and sum of CPML boundary is carried out.By analyzing the distribution of reflection error,the optimal parameters of CPML boundary condition are selected.Both global reflection errors and wavefield snapshots indicate that CPML has better absorption properties than evanescent waves.On the basis of the Matlab platform,a program of elastic staggered forward simulation of rotating staggered grid based on CPML boundary is developed.The program is used to simulate the anisotropic medium and random medium.The seismic wave forward record and wavefield snapshot are obtained.The forward propagation profile and the wavefield snapshots can be used to better understand the propagation characteristics of seismic waves in anisotropic media and random media and to guide the interpretation of seismic exploration data in heterogeneous media.

Transient electromagnetic method, in the area of poor terrain conditions, the transient electromagnetic prospecting method is often not good, the reason: ignore the influence of the terrain factors, resulting in a larger deviation of interpretation results . In this paper, by using the finite difference time domain method to simulate the terrain of transient electromagnetic response, The transient electromagnetic diffusion equation is derived directly from the Maxwell equation, and the finite difference time domain finite difference equation is constructed by introducing the virtual displacement current. First, the analytical model of homogeneous half space solutions were compared with the results of the calculation, test the algorithm accuracy; then, Simulation analysis of the peaks and valley terrain model response characteristics, It?concluded?that the early signal performance for two kinds of features, the front valley terrain, earlier than normal terrain induced electromotive force value decreased, resulting in false high resistivity anomaly, early after than the normal terrain induced electromotive force value increased, resulting in false low resistivity anomalies, mountain terrain features on the contrary, late signal terrain effect gradually weakened; finally, the measured data prove the correctness of this simulation results. The research results have good reference significance for terrain effect recognition and correction.

Traditional deep sea acoustic release transponder has many problems, such as large volume, heavy weight, high cost and difficult dynamic sealing of the driving mechanism. The new acoustic release device program is expected to solve these problems. By contrast, this article determines to use the no-sealing electromagnet to provide the driving force during the release process. A control circuit and mechanical structure were designed. Using the electromagnetic solenoid's inductance change during the release process, throughout a series of transformation of the control circuit, it can recycle the feedback information and realizes the multiplex function of the electromagnet control wires. Though the intermodulation test, the feasibility of the whole scheme is verified. Compared with the existing acoustic releaser, the device has more advantages such as smaller volume and weight, lower cost and other advantages. Meanwhile, the structure is more ingenious and easy to control and deserves further research, and will also provide a useful reference for overall packaging and design of acoustic release transponder.

Several 1D/3D and 2D/3D models were designed for numerical simulation. The authors analyzed the applicability of the three dimensional geological model by using the two-dimensional inversion interpretation method from two aspects, i.e., the difference between the model's 3D response and 2D response and the contrast of the results. Some conclusions have been reached: If the abnormal body is gradually shortened along the length of the strike, the model's three-dimensional characteristics gradually increase. The 2D inversion results using TM polarization mode remain basically unchanged, and the 2D inversion results of TE polarization mode gradually produce distortion, indicating that TM polarization mode has much lower 2D model requirements than TE polarization mode. The effect of 2D inversion of TE/TM mode is usually between the effect of the above two modes, and sometimes better than the two-dimensional inversion result of TM polarization mode. It is concluded that the 2D inversion using TM polarization mode under normal conditions can usually reconstruct original model well, and in the case that the overall electrical characteristics of TE/TM mode inversion results are similar to those of TM polarization mode, the model resistivity value of TE/TM mode inversion result is superior to that of the TM polarization mode.

This paper researched the electromagnetic field theory of the frequency domain airborne electromagnetic method, the boundary conditions, the finite element method and so on. Mainly introduced the mesh generation principle, completed the human-computer interaction mesh generation software and two dimensional finite element numerical simulation algorithm. Understand the characteristics of response of the cylinder model by the simulation calculation. Improved the interpretation level of the frequency domain airborne electromagnetic data.

On the basis of the powerful spatial data management and analysis function of ArcGIS platform, the OGRE graphics engine is used to develop the spatial 3D platform from the bottom, and the three-dimensional urban geological platform based on the T-C-V (terminal-cloud-virtual end) architecture model is designed by using cloud computing technology. Through a unified storage standard, professional analysis methods, common service interface and comprehensive service system, the platform achieves a set of urban engineering drilling data management, multi-source data fusion, regional information services, three-dimensional geological modeling, geological output and sharing, geological data retrieval and other functions in one of the service system. A unified data center is established in the form of services to achieve platform data sharing and interoperability, and then the use of three-dimensional geological data is improved. The established method of prototype system is proved to meet the production requirements in actual use.

The RockPlot software used for plotting of lithogeochemistry is a new attempt which studies the calculation and plotting of geochemical parameters of rocks and processes geochemistry data of rock on computer. The system uses WPF technology and adopts loosely coupled plug-in design to ensure the independence of calculation and plotting of lithogeochemistry, and also to maintain the integrity of the system. Besides, the system applies lightweight data format of JSON that is simple and easy to read and write as a unified configuration module for the calculation and plotting of lithogeochemistry, provides highly flexible expansion function and realizes vectorization output. The system integrates computational and plotting functions, thus providing a comprehensive and integrated application system of lithogeochemistry.

NASVD (Noise adjusted singular value decomposition) is a spectral component analysis procedure for the removal of noise from gamma ray spectra. The procedure transforms observed spectra into orthogonal spectral components. Noise is removed from the observed spectra by rejecting noise components (high order orthogonal components) and reconstructing the spectra from lower order components which are correlated with the signal. The noise of all channels is significantly decreased by this procedure. Three Airborne datasets of survey are processed to discuss the mapping effect with NASVD de-noising. The advantage of large scale mapping with NASVD is much significant compared with traditional average filter. Nevertheless, in small scale situation, they almost show the same result.

The geochemistry survey analysis was conducted on the soil samples collected from the Yixing area in 2004, 2009, and 2015 years, and the results show that the pH-value of surface soil varies from 3.53 to 8.86. Specifically, the acidic soils and strongly acidic soil generally distribute in the distribution of hill sandstone strata. The weak alkaline soil generally distributethe in the distribution of limestone strata. In the alluvial lake plain area, most soil is weakly acidic. And it shows the soil parent material and topographic features impact soil PH-values. Comparing with the changes of the surface soil pH-values within the past six years, the result show that there are 49.77% soils with decreased pH-value, the 23.53% soil with increased pH-valua, and 26.70% soils with relative stable PH-value. Due to the impacts of industrialization development on the environment, the acid rain plays an important role in soil acidification. Affected by farming and among others, the pH-value of surface soil in the alluvial lake plain area are lower than those of deep layer soil by around 1.2. The acidification of the surface soil occurs mainly in the tillage layer, the depth is about 30cm, and the bottom soil is basically neutral. From the general point of view, the analytical results of surface soil in the Yixing area show a trend of acidification. Some necessary measures must be done to prevent further deterioration.

Based on the natural radiation environmental geological survey in the middle east part of Wulian County,the author analyzed the characteristics, distribution and influencing factors of radioactivity. The results show that, in the natural radioactive background of the investigation area, the background value of γ-radiation dose rate is 80.0 nGy/h,and the average annual effective dose of public exposure is 0.46 mSv. The high background area of natural radiation is mainly expressed by the abnormal characteristics of γ-radiation dose rate and the radionuclide ²³²Th content,and its main lithology includes monzogranites and biotite monzonitic granitic gneiss. In the investigation area, the radionuclide concentration in water supply, river and water well is low, and hence the water source is safe.

The geological exploration methods for geological faults include shallow seismic exploration, electrical joint section method, resistivity sounding, electrical resistivity tomography, geological radar and transient electromagnetic method. The distribution of geological structure can be detected from the velocity and relative permitivity. From the distribution of activities of faults, geological data, remote sensing data and isotope or thermoluminescence dating techniques, a scientific evaluation can be made. The above research would be important for the rational use of the site and the safety of the layout of the project. In this paper, the geophysical prospecting of a cement production line in Changchun serves as an example to discuss the exploration and activity evaluation of geophysical methods for concealed ruptures.

The early quadratic field of the transient electromagnetic method is the response of shallow geological information. The self-induction electric field generated by a shut off of primary field is superimposed with the early secondary field, which causes the results that the detection result can't reflect the shallow stratum information and form a shallow blind area, and that the detection of early pure secondary field can fundamentally eliminate shallow blind spots. This paper first introduces the coil device of the opposing coils transient electromagnetic method, illustrates the method of the early secondary field acquisition, and meanwhile briefly describes the zero flux surface and the analysis of the regularity of induced voltage. Taking the karst exploration of highway slope of a hydropower station as the research background, the authors obtained the apparent resistivity information of strata of different depths, and delineated the spatial distribution of karst based on the analysis of the inversion results of the test data. It is proved that the opposing coils transient electromagnetic method can effectively avoid the impact of primary field shutdown on the secondary field, basically eliminates the shallow blind zone, and realizes the accurate exploration of the shallow stratum.

In the in-situ test of ground thermal properties for vertical tubes, simplified analysis method is frequently applied to calculating the thermophysical parameters of rock and soil mass. Integrated thermal conductivity and borehole thermal resistance are worked out then. This method may result in different levels of error under variable test conditions. In this paper,based on the heat transfer numerical method,the authors studied the main factors that influence the thermal conductivity and the borehole thermal resistance accuracy, such as circulation medium flow rate, loading power, interval between two tests, performance of test equipment, depth of test holes, thermal conductivity of backfill material, seepage in rock and soil mass, and geothermal gradient. Based on the calculation results of heat transfer, the authors put forward methods for reducing the calculation error of linear heat source:Selecting relatively reasonable test parameters according to the test conditions, eliminating the system error by the model experience correction method or using improved numerical models.