Details of the Abstract
| Title of paper | CSEM sounding strategy based on the total magnetic field |
| List of authors |
Diquan, Li., Yunqi, Zhu., Yanfang, Hu |
| Affiliation(s) |
School of Geosciences and Info-Physics, Central South University, lidiquan@csu.edu.cn School of Geosciences and Info-Physics, Central South University, yunqizhu@csu.edu.cn School of Geosciences and Info-Physics, Central South University, huyf90@csu.edu.cn |
| Summary |
Problems such as angular errors and zero-value bands in single-component acquisition of electromagnetic fields in Controlled-Source Electromagnetic Method (CSEM) are becoming more and more prominent, especially in areas with complex terrain. We proposed a sounding strategy using the total magnetic field, which can be synthesized from orthogonal three-component magnetic fields. Simulation results show that the total magnetic field is uniformly distributed in all directions of the field source, with no zero-value bands and a larger detectable azimuthal angle range. Since the total magnetic field is constant at a fixed station, it is unaffected by angular errors due to attitude changes of sensors. Theoretical analyses indicate that a three-component magnetic field sensor can be used for total magnetic field sounding. An experiment was conducted in Chongqing, China, targeting an artificially excavated group of buildings in a mountain at a depth of about 150 m. The total magnetic field was synthesized by simultaneously collecting the vertical magnetic field component and the orthogonal two-component horizontal magnetic field on the ground. Experimental data show that the total magnetic field exhibits a clear high-resistivity anomaly in response to the target. Comparison of the results between the total magnetic field and the ground electric field shows that the former responds more significantly to target detection, while the latter is heavily influenced by static effects. Additionally, it should be noted that the magnetic field data analysed in the experiment was not denoised, yet the data remained high quality. This indicates that the total magnetic field has outstanding immunity to interference. And it is unnecessary to monitor or control the tilt precisely because the measurement system provides rotationally invariant total field data. It is expected to further reduce the lowest frequency available in semi-airborne electromagnetic method (SAEM) and increase the depth of sounding. |
| Session Keyword | 1.0 Instrumentation, data acquisition and processing |
| File upload |
1.0_csem_sounding_strategy_ba_zhu_01.pdf
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