1887

Abstract

Summary

The GREATEM (GRounded Electrical source Airborne Transient ElectroMagnetics) survey uses a grounded electrical dipole source of 2∼3 km length as a transmitter and a three-component magneto-meter in the bird towed from a helicopter as a detector. The GREATEM system is considered to be an airborne version of the Long Offset Transient ElectroMagnetics (LOTEM) system ( ). We developed a numerical forward modelling scheme using a staggered-grid finite-difference method (SFD, ) adding a finite-length electrical dipole source routine. To construct a three dimensional (3D) resistivity model for GREATEM data, we have to overcome to compute a model composed of huge number of grid at wide frequency ranges because GREATEM has obtained resistivity data in time domain at a large number of sites.

In order to verify the validity of the code, we compare the results with those obtained by the 2D numerical code of the LOTEM case developed by for a 2D quarter space model and a trapezoidal hill model. Finally, we simulate GREATEM responses for 3D modeling with a conductor placed at coast-land boundary and a topography model.

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/content/papers/10.3997/2214-4609.20142036
2014-09-08
2020-02-23
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