What is Geophysical Surveying? The Ultimate Technology Guide

1. Core Concepts & Method Classifications

1.1 Definitions & Scientific Basis

Geophysical Surveying is a non-destructive technique that infers subsurface structures by measuring anomalies in geophysical fields (electromagnetic, seismic waves, gravity, etc.). It is categorized into:

• ​Passive Methods: Utilize natural fields (gravity, geomagnetism)1
• ​Active Methods: Employ artificially induced fields (electrical currents, seismic waves)4

Technical Essence: Inversion algorithms convert surface data into subsurface physical property distributions, with resolution exponentially decreasing with depth

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1.2 Mainstream Method Matrix

Method	Physical Parameter	Detection Depth	Typical Equipment
​High-Density Resistivity (HDR)	Resistivity	10-500m	Geotech GIM
​ERT	3D Resistivity	5-300m	Geotech WGMD
​GPR	Dielectric Constant	0.1-30m	Geopro T-Series
​Seismic	Wave Velocity/Impedance	50-5000m	GE-ANT-Series

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2. Technical Comparisons & Innovations

2.1 Resistivity-Based Methods

High-Density Resistivity Method

• Principle: Automated multi-electrode arrays (60-120 channels) generate 2D/3D resistivity profiles4
• Advantages:
  • 5x faster data acquisition than traditional DC methods (2km/day coverage)1
  • Digital filtering achieves 80dB SNR in urban environments7
  • Identifies karst conduits <5m diameter (±2% accuracy in Wuhan case)1

ERT (Electrical Resistivity Tomography)

• Innovations:
  • ConvResNet AI inversion reduces 3D modeling from 24h to 1.8h5
  • 1000V high-voltage system enables 300m penetration (<8% error in coal mine void detection)4

2.2 Electromagnetic Wave Methods

GPR (Ground-Penetrating Radar)

• Frequency Selection:
  • 100MHz：Municipal pipeline detection (10m depth, 0.3m resolution)2
  • 2.6GHz：Concrete defect inspection (0.5m depth, 2cm resolution)7
• Case Study: Located 16.5m-deep karst cavities in Malaysia limestone sites6

2.3 Advanced Seismic Applications

• ​Microseismic Monitoring: ±3m positioning accuracy for CO₂ storage leakage warning1
• ​Surface Wave Survey: MASW technique inverses shear wave velocity within 50m depth5

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3. Industrial Applications & Cost Efficiency

3.1 Urban Geohazard Prevention

• ​Subway Tunnel Inspection: GPR+MSSW combination detected boulder clusters in shield zones (30% risk reduction in Beijing projects)4
• ​Karst Collapse Warning: ERT-OCTEM integration improved karst detection accuracy to 92% in Wuhan1

3.2 Mineral Resource Exploration

• ​3D Orebody Modeling: 3D ERT differentiated silicified zones (ρ>2000Ω·m) with 40% cost reduction4
• ​Coal Mine Void Detection: TEM+HDR synergy defined aquifer boundaries (12,000m³/day water drainage reduction in Xinjiang)1

3.3 Environmental Engineering

• ​Pollutant Monitoring: TEM+ERT mapped VOC plumes with 0.1ppm sensitivity4
• ​Permafrost Thaw Early Warning: UAV infrared + microtremor tech enabled dynamic monitoring15

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4. Equipment Selection & Technological Breakthroughs

Product Line	Key Innovations	Application Scenarios
​ERT	120-channel AI switching	3D metal ore modeling
​Radar	Multi-frequency synchronization	Urban road collapse warning
​SeisNode	500-node wireless network	Site seismic risk assessment

Explore Advanced Solutions
Visit www.geotechcn.net for technical specifications and case studies

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References

1: Multi-geophysical methods for permafrost thaw monitoring on Qinghai-Tibet Plateau (Engineering Geology 2025)

2: GPR advancements in mineral exploration (ResearchGate 2023)

4: Integrated geophysical assessment of permafrost engineering risks (Engineering Geology 2025)

5: Machine learning applications in ERT and seismic methods (Geophysical Journal 2024)

6: GPR applications in Malaysian limestone sites (Geotomibased 2024)

7: Real-time GPR inversion using deep learning (Oxford Academic 2024)