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VLF Tipper Mapping Using a Mobile 3 Component Magnetic Antenna
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
Far from its sources and in the presence of conductivity variations in the ground, the vertical and horizontal components of the VLF magnetic field can be linked by a linear equation: H_z=AH_x+BH_y.
The components A and B are called the tipper vector and inform us about the ground conductivity changes. By mounting an ADU data logger and a SHFT antenna from Metronix geophysics on a homemade trolley, we investigate the possibility of profiling and mapping with the tipper vector. We carried out a survey with seven profiles on a site next to Reims in France. The low electromagnetic pollution of the area allow us to record many VLF frequencies (nine) and to run many tests, considering the direction of the various VLF sources. Finally, after choosing two frequencies, we calculated the tipper vector on the whole survey area. The first results show a good spatial resolution and a strong capability of detection. We were able to precisely map a buried pipe. Moreover, the comparison with a magnetic map showed a very good fit between the data.