Hello Birhanu Ermias,

Any geophysical method that can map lithostratigraphic sequence can be used in mapping fault orientation. Even though, you did not provide any information on the depth to the fault from geological data, the particular technique to be adopted depends on the depth and dimension of the faults. If the faults are deeply seated, then Ground Penetrating Radar may not be useful at the present level of technology because the technique uses very high frequency signals that have poor penetration power. Other techniques like electrical resistivity tomography (ERT) and seismic reflection can help in mapping the dimensions of the fault. The capacity of the ERT to optimally model the fault depends on the availability of space to spread the cables since penetration depth is about 30.33% of the electrode separation. Thus, if the faults are deeply seated, you require a large space and long length of cables model it.

I hope these suggestions will help.

Dear Birhanu Ermias

The magnetic studies by convenient methods of survey and interpretations are showing promising results for fault identifications and evaluation of their subsurface characteristics. Although, there is very little literature available for the same but there is sufficient material available according to your question.

Thank you

cheers

Thank you @Anthony E. Akpan for your very useful suggestion. Information regarding the depth to the fault from geological data is about 22 meters.

With respect to electrical resistivity tomography (ERT) and seismic reflection/refraction, which one can better determine the dimensions of the fault? Thank you.

Thank you @Anthony E. Akpan for your very useful suggestion. Information regarding the depth to the fault from geological data is about 22 meters.

With respect to electrical resistivity tomography (ERT) and seismic reflection/refraction, which one can better determine the dimensions of the fault? Thank you.

The zone of influence of the fault in the horizontal plane can be identified by installing symmetrical electric profiling of the AMNB with dimensions: AB= 80-100m, MN=10 m, the research step is 5-10 m.

The depth (amplitude) of the disturbance can be determined by seismic survey: the method of reflected waves.

The activity of the fault or its parts (dynamics) can be determined using the alpha-track method based on the density of particle tracks on the photoemulsive film

The zone of influence of the fault in the horizontal plane can be identified by installing symmetrical electric profiling of the AMNB with dimensions: AB= 80-100m, MN=10 m, the research step is 5-10 m.

The depth (amplitude) of the disturbance can be determined by seismic survey: the method of reflected waves.

The activity of the fault or its parts (dynamics) can be determined using the alpha-track method based on the density of particle tracks on the photoemulsive film. [email protected]

Use a combination of geoelectrical de tion dipole_ dipole combined with seismic refraction. The seismic unit st least 24 channels

Both Magnetic and ERT/EM methods, quite convenient and easy to use, should be enough to give you success, I suggest you integrate the 2 methods to complement each other. With inversion tools(Oasis Montage, Res2DInv, or ZondRes2D) and numerous filtering algorithms for the two methods, you should be able to image the subsurface and interpret.

A dipole-dipole configuration with 3m electrode spacing and n=20 should offer a high resolution for ERT though with larger datasets. If constrained by number of electrodes use the roll-along technique and and merge the whole data later on. Best of Luck!

It appears to me that the previous answers relate to each responder’s pet technique.

The question was, “Now, it is required to determine the exact position (orientation and width) of the fault zones to design appropriate foundation treatment measures before starting construction.”

A three-dimensional seismic survey designed to focus on very shallow horizons with geophone locations closely spaced, and utilizing a high-frequency energy source will answer the question.

To answer this question, you must know the depth of investigation to select the suitable geophysical method (thickness of channel deposit )

Dear Birhanu Ermias

In the next I will give geological geomorphological method... Try to study macro enviroment. perhaps from it you will be able to use the previous response... If you have opportunity to determine the macro structure of basement from the neighbour natural oppening if exist... If you have opportunity, make microgeomorphological study...

Regards,

Laszlo

The zone can be identified by installing symmetrical electric profiling of the AMNB with dimensions: AB= 80-100m, MN=10 m, the research step is 5-10 m.

Integrating magnetic, EM and ERT techniques can suffice. However, efforts have to be made in ensuring good penetrations in the chosen methods.