Three-dimensional forward modeling and quantitative assessment of electrode offset effects in ERT

Area of Science:

• Geophysics
• Electrical Resistivity Tomography

Background:

• Resistivity data is vital for geophysical exploration.
• The influence of electrode offsets on resistivity responses is not fully understood.

Purpose of the Study:

• To investigate the impact of horizontal electrode offset angles and vertical offsets from topography on resistivity forward modeling.
• To analyze how these factors affect the detection of buried targets and the resolution of resistivity data.

Main Methods:

• Conducted 3D resistivity forward modeling using ZondRes3D.
• Analyzed experimental models with various measurement arrays.
• Examined the effects of different horizontal electrode offset angles and topographical variations.

Main Results:

• Horizontal electrode offsets generate pseudo-anomalies in apparent resistivity, influenced by offset angles and electrode count.
• These offsets create a 'gradient variation' pattern in the data.
• Topographical variations cause distortions and shifts in apparent resistivity curves and anomaly locations, particularly affecting measurements near target edges.

Conclusions:

• Horizontal electrode offsets and topographical variations significantly impact resistivity data interpretation.
• Offset angles influence pseudo-anomaly characteristics.
• Topography affects anomaly detection and location accuracy, especially near target boundaries.
• Findings guide improved data processing and survey design in electrical resistivity tomography.