Field Testing of a Controlled-Source Wide Frequency Range Magnetotelluric Detector Using SQUID and Inductive Magnetic...

Area of Science:

• Geophysics
• Electromagnetism
• Geological Surveying

Background:

• Shallow geological structure detection requires high-resolution geophysical methods.
• Existing magnetotelluric systems have limitations in frequency range and sensor compatibility.
• Advancements in instrumentation are crucial for detailed subsurface exploration.

Purpose of the Study:

• To develop and validate a Controlled-Source wide frequency range Magnetotelluric Detector (CSUMT) for enhanced shallow geological structure detection.
• To compare the performance of inductive and Superconducting Quantum Interference Device (SQUID) magnetic sensors within the CSUMT system.
• To assess the reliability and practicality of the CSUMT system in complex geological settings.

Main Methods:

• Development of the CSUMT system with a 1 Hz to 1 MHz frequency range, 24-bit ADC, and compatibility with inductive and SQUID magnetic sensors.
• Systematic field experiments conducted in Fengxian County, Shaanxi Province.
• Comparative analysis of CSUMT data with a commercial V8 instrument and direct comparison of inductive versus SQUID sensor performance.

Main Results:

• The CSUMT system demonstrated high consistency with commercial instruments in electric field, magnetic field, and apparent resistivity measurements.
• SQUID magnetic sensors exhibited lower noise and more stable data output compared to inductive sensors across the tested frequency range.
• The CSUMT system proved practical and reliable for geophysical surveys in complex geological environments.

Conclusions:

• The developed CSUMT system is a reliable tool for high-resolution shallow geological structure detection.
• SQUID magnetic sensors are recommended for broad-frequency magnetotelluric surveys due to their superior performance.
• The study provides valuable experimental data supporting the use of advanced magnetotelluric techniques in geological exploration.