Fullagar Geophysics EmaxAIR 5.81a: Airborne TEM Conductivity-Depth Imaging Software

Fullagar Geophysics EmaxAIR 5.81a is a specialized software program designed to rapidly transform airborne transient electromagnetic time decays into conductivity-depth pseudo-sections (CDIs) . The program is a key tool for geophysicists who need to quickly interpret airborne EM data and understand the distribution of subsurface electrical conductivity. It is part of the suite of geophysical interpretation tools developed by Fullagar Geophysics and can be run as a stand-alone application or integrated with the broader Maxwell geophysical interpretation software platform .

The EmaxAIR algorithm was originally developed by P.K. Fullagar and J.E. Reid as an adaptation of the ground-based Emax method for airborne TEM data . The transformation process involves two stages: first, the apparent conductivity is determined at a given delay time; second, the depth of the current maximum in a half-space with conductivity equal to the apparent conductivity is adopted as the apparent depth at that time . This approach provides a rapid and convenient form of preliminary interpretation for airborne EM data . A key advantage of the Emax transformation is its adaptability to a wide variety of TEM data types 

👥 Primary Users

This specialized geophysical software is designed for:

  • Exploration Geophysicists processing and interpreting airborne transient electromagnetic (TEM) data for mineral exploration and geological mapping .

  • Environmental & Hydrogeological Consultants mapping groundwater, salinity, and contamination using airborne EM surveys .

  • Geological Survey & Government Agencies conducting regional conductivity mapping for resource assessment.

  • Academic Researchers studying subsurface conductivity structures and electromagnetic methods.

⚡ Key Features & Capabilities

 

🧮 Conductivity-Depth Imaging (CDI)

  • Rapid Transformation: Quickly converts airborne TEM decays into 2D conductivity-depth pseudo-sections, providing an immediate visual representation of subsurface conductivity .

  • Apparent Conductivity & Depth: Determines apparent conductivity at each delay time, then estimates apparent depth based on the depth of maximum current in a half-space of that conductivity .

  • Sharpening Option: EmaxAIR includes a “sharpening” process that treats the initial apparent conductivity as a depth average, then inverts it to produce improved depth resolution of conductive layers .

📊 Data Output & Visualization

  • CDI Sections: Generates conductivity-depth sections for individual flight lines (e.g., .CDI files) .

  • Depth Slices: Computes average conductivities for defined depth intervals (e.g., 0-10m, 10-20m, 20-30m, etc.), which can be exported as ASCII data or ERMapper grids .

  • ASCII Format: Outputs data in a structured ASCII format containing line number, coordinates, depth, apparent conductivity, and other parameters .

🔧 Processing & Workflow

  • Stand-Alone or Integrated: Can be run independently or directly through Maxwell software, offering flexibility for different workflows .

  • Variable Current Accounting: Takes into account variable transmitter current during processing .

  • Data Fitting: Apparent conductivity is computed via single-parameter inversion, fitting data to an accuracy specified by the user .

  • Versatile Data Handling: Supports a variety of airborne TEM systems and data types, including GEOTEM_DEEP and HoistEM data .

🆕 What’s New in Version 5.81a

  • Enhanced Sharpening Algorithm: Improved depth resolution of conductive layers through advanced sharpening techniques .

  • Broader Compatibility: Updated to support newer airborne TEM systems and data formats.

  • Performance Optimizations: Faster processing for large datasets and improved workflow integration.