• Multi-Model
  • Gravity Heath Steele
  • Gravity Synthetic Model
  • Magnetic Example
Multi Model Magnetic and Gravity Gradiometer.
  A new Inversion technique for magnetic and gravity gradient profile data supporting up to 5 bodies in a given model scenario. Developed by Scott Hogg and Associates.
   

Gravity: Heath Steele example.
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Gravity Muli-Mod lets you discover the possible geologic source of anomalies mapped by airborne gravity gradiometers.

The example presented is from a Bell Geospace Air-FTG survey over the Heath Steele area of New Brunswick. The data was provided by the New Brunswick Department of Natural Resources. The nominal flight line spacing was 200 m. and the full gravity tensor was recorded. This example uses both the Gzz and Gzy tensor component profiles.

The Multi-Mod map view, shown on the left, presents the Gzz grid as a background image. In this window the user defines the axes of one or more density anomalies and a section of flight line that crosses them. This combination of 1 to 5 bodies and a crossing profile is the model scenario illustrated below. The option to fit Gzz in combination with Gzy is has been selected.

This inversion presents the form, depth and density contrast of 3 bodies that would provide a good fit to the observed profiles of Gzz and Gzy. This is a possible but not a unique explanation for the gravity profiles. The user may fix parameters such as width and density to find a solution that best accommodates known geological constraints.

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  Multi-Mod: Heath Steele examplel.pdf
Gravity: Synthetic Model.
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Few tools are available to model isolated density anomalies measured by airborne gravity gradiometers. The Multi-Model approach uses the measured Gzz plus the Gzx or Gzy profiles and allows the inclusion of adjacent bodies and their anomalies to be included in a single analysis scenario. All of the bodies individual model parameters can be optimized simultaneously in combination. The process is simple, efficient and flexible.

  • Start with a map image of Gz, Gzz or other grid of your choice.
  • Interactively define the density axes of the bodies of interest.
  • Point to a crossing flight line in the profile database and highlight the section to be modelled.
  • Select the magnetic axes of interest to compose the modelling scenario.
  • Activate from 1 to 5 bodies and control the inversion of a single body or a multi-body combination.
  • If desired, include Gzx or Gzy profiles to further constrain the fit.
  • The quality of fit, and the influence of each body, is visually displayed.

Illustrated above is the result of a combined optimization of 2 density bodies. The inversion has included both the measured Gzz and Gzy profiles. This graphic image is generated to visually record the modelling result. As well, all of the body parameters are saved in a master project database. The contents of the table can be plotted on a map in a variety of numeric and symbolic formats.

  Multi-Mod: Synthetic Model.pdf
Magnetic example.
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Many tools are available to model isolated magnetic anomalies but in practice such simple scenarios seldom exist. The Multi-Model approach allows adjacent bodies and their anomalies to be included in a single analysis scenario. All of the bodies individual model parameters can be optimized simultaneously in combination. The process is simple, efficient and flexible.

  • Start with an image of total magnetic field, vertical gradient or other grid content of your choice.
  • Interactively define the axes of the magnetic bodies of interest.
  • Point to a crossing flight line in the profile database and highlight the section to be modelled.
  • Select the magnetic axes of interest to compose the modelling scenario.
  • Activate from 1 to 5 bodies and control the inversion of a single body or a multi-body combination.
  • The quality of fit, and the influence of each body, is visually displayed.

Illustrated above is the result of a combined optimization of 5 magnetic bodies. This graphic image is generated to visually record the modelling result. As well, all of the body parameters are saved in a master project database. The contents of the table can be plotted on a map in a variety of numeric and symbolic formats.

  Multi-Mod: Magnetic example.pdf