五. 地球物理观测技术的新进展及新应用
（负责人：刘宝成 陆其鹄）
The New Development and Application of
Geophysical
Observations and Experimental Technique
(Conveners: LIU Baicheng LU Qihu)
1. The Application of GPR
to Karst detection
Mo Han Deng Juzhi
(East China Geological
institute, LinChuan, 344000)
Abstract: Ground penetrating radar is an important method in engineering exploration. From analysis the image signature of GPR, people can find out the distribution of different electrical medium underground. While collecting GPR data in the field, we must choose appropriate parameters according to the working tasks and working objects. A role of GPR played in karst exploration on the WuHu—XianCheng expressway is introduced in this paper. We successfully outlined the positions of karsts in that region. And the results of GPR are very similar with drilling results. So the GPR data provided enough basis to handle that region.
2．模型井中声电转换波场的实验研究
作者：胡恒山 李长文 王克协
Experimental
study on electrokinetically converted
acoustic
and electric fields in a borehole
HU Hengshan，LI Changwen，Wang Kexie
Electrokinetic experiments are conducted at acoustic logging
frequency in model wells with of different formations. One is a formation
consisting of two parts, with a permeable glued-sand on top of a lucite. The
other is full-diameter sandstone core from target formation. The cation
exchange capacity for both the glued-sand and the target sandstone is very low.
We recorded electric waveforms that accompany the acoustic waves in permeable
formations. There is no such electric field in the lucite section of the
borehole. The higher the salinity, the weaker the acoustically induced electric
field. Propagating electromagnetic waves that generated at the boundary between
the lucite and the permeable formation was also observed. That kind of electric
field propagates in the lucite as well as in the glued-sand. The relative
amplitudes of these two kinds of acoustically induced electric fields depend on
formation salinity and its difference with borehole fluid salinity. We also
measured acoustic waves in each of the two boreholes when an alternating
electric signal was excited. Most of the results are in consistent with Pride
theory.
Acknowledgements. We should thank
Dr.Zhenya Zhu at Massachusetts Institute of Technology for his advice on the experiments.
HU
Hengshan and WANG Kexie
Dept of Physics,
Jilin University,
Changchun,130021
China
LI
Changwen
Jianghan Well Logging Institute
Qianjiang, Hubei, 433123
China
3．The Method and Application
Effects of
Pseudo-seismic Interpretation of TEM
Li XiuGuo wenbo
(ChangAn university Xi'an 710054)
Being
a method of time-domain electrical magnetic prospecting, the
Transient Ele ctromagnetic Method is so wide to be used in the field of
resource
prospecting a nd engineering exploration. Based on the Similarity between
the
electromagnetic wave and Seismic wave, the pseudoseismic
interpretation of
electromagnetic exp l oration has been a popular topic in geophsical field at
present.
This paper full y discusses the Law of propagation of electromagnetic
wave and Seismic wave in m edium,
and analyses the kinematic features of transient impulse
electromagnetic field.
According to the harmony between the observational results of
Center-loop device and MT,
this paper proposes to explain TEM data with the pseudo-seismic
interpretation.
The forward and inversion calculated result of a host of theoret ical
model examples
indicates that the theory is right, the processed results of the field
data further
demonstrate that this method is useful and practical.
5．LGM-2000 high-density resistivity method meter
Liang Qingjiu Liang Yongren Luo Yanzhong
China University of Geosciences, Wuhan, 430074
1. AC Low frequency power supply, frequency adjustable, can measure the resistivity and polarizability. This makes the function of AC IP survey reality.
2. Using military weak signal detection technique and high accuracy 24 bit A/D converter realized the high accuracy measurement.
3. Main control meter is notebook or pocket computer, which working in full Chinese characters based on the Windows environment.
4. Using 2D inverse software of high-density resisitivity method.
5. Intelligent electrode gating technique: using a 10-wire cable and at most may realized 1024 electrode array switching and measurement.
6. Electrode switch adopt stainless steel case, full hermetically sealed construction and make it can work in water.
7. Power supply system adopts all exempt maintenance accumulator and switch power technique.
6. 特殊场地条件下电法勘探的应用
汤洪志
刘庆成 易峰
（华东地质学院，江西抚州，344000）
Applications of Electrical Method
Exploring in Special Fields
Tang Hongzhi Liu qingcheng et.al.
Applications of Electrical Method Exploring in Special Fields
Tang Hongzhi Liu qingcheng et.al.
(East of China geology institute, jiangxi fuzhou 344000)
In process of city engineering and environment geophysical prospecting，we have asked frequently to carry through the electrical method exploring in some special fields. For example, sometimes we have to carry through the electrical method exploring on cement roads and in water sometimes. This paper discussed the ways how to earth with special electrode made by ourselves on cement roads , at the same time, talked over characteristic of water electrical method exploring.
7. 基于小波分析的带阻滤波技术在MT数据处理中的应用
何兰芳 王绪本
（成都理工学院地球物理系，成都，610059）
(Dept
of Geophysics, Chengdu University of Technology, Chengdu, 610059)
Abstract Artificial cultural noises, such as industrial power, often bother the data acquirement and data processing of Magnetotelluric Sounding (MT). Although many methods, such as crosspower method and remote reference-channel method etc., had been introduced to solve this problem, the results were unsatisfactory. Compared with Fourier Transform, wavelet analysis has a time-frequency variable filter window, being more powerful in the filtering processing. Therefore, it is more effective to be used to construct the notch filter for MT data processing than Fourier Transform. In this paper, we focus on discussing the notch technique construction, the detecting of noises by wavelet analysis, as well as their application in MT data processing. In addition, two examples have been mentioned in brief.
Keywords:
Wavelet analysis, Notch technique, MT data processing