The present paper briefly describes methods and techniques of field work, data-Processing and interpretation adopted in shallow seismic exploration for solving engineering geologic problolns as well as the working method of"five small and two high",and discusses the necessity of using wave method in combination with the reflected wave method.The results show thatshallow seismic exploration can play a unique role in finding out buried depth of bedrock anddetecting faults,thus Providing fairly accurate and reliable geologic basis for overall distributionof industry in the development area.

The Present paper recommands the Po-210 technique for detecting geologic structuresof coal mines,which is a new application of nuclear technique in geosciences.With this technique,ono caac detect concealed faulted Structures, concealed deprossion pillars,mined-out areas ofold workings and seam floor with well-developed water-filled fissures in coal minos.Therefore,this technipue is a rapid and economic means for tackling geologic and waterproof problems iucoal mines.Basic principles,working method, data-Processing method,detection examples and application prospects of this technique are dealt with in this paper.

The Present paper gives a generalized description of 93 International Symposium on Airborne Electromagnetic Method aam the present condition of airborne electromagnetic method abroad. Based on an analysis of the Present condition of China's airborne electromagnetic survey,the paper probes into the problem concerning the development of China's airborne electromagnetic survey at the presage stage.

Airborne electrical method of China is now in a crucial period of acceptance or rejection and storage.This is a matter of great importance,about which aerogeophysicists,especially airborne electrical workers,show much concern.This paper makes a comprehensive description in such aspects as the development history of airbone electrical method,the application of this method,and the geological ac ore-prospecting achievement as well as economic benefitgained by this method.Through a comparison with airborne electrical method abroad,the presentpaper also shows technical level of the airbone electrical work in China and ito prospects ofdevelopment and application.

In combination with geoelectric model,the present paper gives the curve showing thevariation of calculation error with optimized wave numbers, revealing the existence of an abruptlydropping stable point.This regularity greatly reduces the wave numbers that calculation requires.In addition,studies show that an abruptly-dropping stable Point is also existent on the curveshowals varistion of etror with density parameter of network.The discovery of this regularitycan considerably reduce the time of two-dimensional finite element direct calculation, and makepossible its full application in the inverse problem.

The present paper first discusses record rules in electromagnetic sounding of frequencydomain,and then makes a Specific analysis of simulation results with three-dimensional numericalvalues. The authors believe that,if the weall shading effect is not considered, it is moro reasonable to regard the sounding point as the frequency record point.This has been supported by fieldtest and comparison.

In inverse interpretation of gravity data,the regularized solution of linear equa-tionsset is an effective method.This method is characterized by introducing regularized factorsevaluating functional minimum and constructing a group of regularized approximate solutions with the desire of seeking for optimum solution.In the process of estimation,it is necessary that there exists in advance a preliminary inference and interpretation for the solution to be obtained.Therefore,one must first make fairly detailed study on the problem to be interpreted,and carry out a comparison on apriori data obtained by integrated utilization of various methods and meansso as to put forward a comparatively desirable fundamental expected value.The present paper gives a transverse profile of theoretical model with known parameters,and a comparison of the result of the regularization method and that of other methods for solutionof linear equations set shows the effectiveness of the regularization method.The paper also describes the effectiveness of utilizing the regularization method to make inverse interpretationfor a geological-geophysical profife across Luzon island and Manila Trench as well as a geologic al-geophysical investigation profile in the sea area of South Yellow Sea.

According to exploration seismic sounding data,density stratification wag fixed forgravity anomalies along the Fenghuang-Chaling geoscieroe section.The section density model wasessablished with the help of variable density horizontal trapezoid body,ac th6 calculated theoretical anomalies are coincideal with the measured Bouguer gravity anomalies.The Bouguer gravity anomalies can be reasonably interpred on the basis of the section density model.The earth crust was divided also sedimentary cover, metamorphic layer aam gramlito layer,with the gravity effect curves of these three layers and the gravity effect curve of the upper mantle low densitybody calculated respectively.In addition,the gravity anomaly curve caused by MOho reliefwas calculated, and various factors aam characteristics that give rise to crustal gravity anomalieswere analysed.

According to data available,the present Paper dealt prelimboily with the problemof concentration clarke values used traditionally by some regions geochemists for estimatingenrichment and impoverishment of different elements in different geological units.On such a basis,a new method for calculating regions concentration coefficients has been advanced in whichaverage regional background values of elements are used instead of their clarke values in thecrust,and the regional spatial distribution patterns of trace elements have been Studied,with fairly good results obtained.