Abstract
Exploration for geothermal resources is often challenging because
there are no geophysical techniques that provide direct images of
the parameters of interest, such as porosity, permeability and fluid
content. Magnetotelluric (MT) and seismic tomography methods yield
information about subsurface distribution of resistivity and seismic
velocity on similar scales and resolution. The lack of a fundamental
law linking the two parameters, however, has limited joint interpretation
to a qualitative analysis. By using a statistical approach in which
the resistivity and velocity models are investigated in the joint
parameter space, we are able to identify regions of high correlation
and map these classes (or structures) back onto the spatial domain.
This technique, applied to a seismic tomography-MT profile in the
area of the Gro\Schönebeck geothermal site, allows us to
identify a number of classes in accordance with the local geology.
In particular, a high-velocity, low-resistivity class is interpreted
as related to areas with thinner layers of evaporites; regions where
these sedimentary layers are highly fractured may be of higher permeability.
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