
TY  - JOUR
A1  - Sattel, Daniel 
T1  - The resolution of shallow horizontal structure with AEM
JF  - ASEG Extended Abstracts
JO  - ASEG Extended Abstracts
Y1  - 2003
VL  - 2003
IS  - 2
SP  - 1
EP  - 5
KW  - 
UR  - https://doi.org/10.1071/ASEG2003AB154 
N2  - The minimum size of shallow horizontal structures to be detectable and resolvable with airborne electromagnetic (AEM) systems is discussed. Synthetic data were generated for the helicopter frequency-domain system RESOLVE and the fixed-wing time-domain systems TEMPEST and GEOTEM. The modelled scenarios include conductive prisms in a resistive host and resistive prisms in a conductive host. The EM responses of these models were computed for a range of prism thicknesses, side-lengths and host conductivities. Gaussian noise in amplitude comparable to actual system noise levels was added to the synthetic data followed by the derivation of conductivity-depth sections via three-layer inversion and EMFLOW conductivity-depth imaging. Where these 1-D algorithms failed to indicate the presence of the prism the data were inspected for prism anomalies in order to evaluate if 2-D or 3-D algorithms might be able to map these structures. The results indicate that beyond a minimum prism conductance (conductivity-thickness product), prism thickness and host conductivity are much less important than side-length. For horizontal prisms to be detectable with the RESOLVE system they have to be at least 12 m wide. In order to resolve their thicknesses and conductivities with 1-D algorithms, the prisms must be at least 130 m wide. For the TEMPEST and GEOTEM system the application of 1-D algorithms enables the detection of horizontal prisms wider than 180 m and the resolution of their thicknesses and conductivities for prisms wider than 450 m. Profile inspection shows that horizontal structures as narrow as 24 m might be detectable with more advanced algorithms. 
ER  -

