Publication Date:
2015-04-19
Description:
We present 1D anisotropic inversion of magnetotelluric (MT) data as a potential tool for mapping structural permeability in sedimentary basins. Using 1D inversions of a 171 site, broadband MT data set from the Koroit region of the Otway Basin, Victoria, Australia, we have delineated an electrically anisotropic layer at approximately 2.5 to 3.5 km depth. The anisotropy strike is consistent between stations at approximately 160° east of north. The depth of anisotropy corresponds to the top depth of the Lower Cretaceous Crayfish Group, and the anisotropy factor increases from west to east. We interpret the anisotropy as resulting from north–northwest oriented, fluid-filled fractures resulting in enhanced electrical and hydraulic conductivity. This interpretation is consistent with permeability data from well formation tests. It is also consistent with the orientation of mapped faults in the area, which are optimally oriented for reactivation in the current stress field.
Keywords:
Marine Geosciences and Applied Geophysics
Print ISSN:
0956-540X
Electronic ISSN:
1365-246X
Topics:
Geosciences
Published by
Oxford University Press
on behalf of
The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
