Detecting lineaments in Northern Bavaria from magnetotelluric soundings

Northern Bavaria shows an elevated surface heatflow in combination with prominent lineaments
and potentially hydraulically active tectonic faults. Sharp resistivity contrasts, as they might appear
for geothermal fluids migrating along faults and altering the host rock resistivity environment, are
an ideal target for electromagnetic measurements. Magnetotelluric (MT) measurements have been
conducted in northern Bavaria in October 2019 for the investigation of the subsurface resistivity
structure of the lineaments and faults for possibly future geothermal explorations. Magnetotelluric
data sampled in highly populated areas are often contaminated with anthropogenic electromagnetic
noise and result in strong outliers in the impedance tensor estimates. A robust remote reference
method and several pre-stack data selection criteria have been applied in order to retrieve meaningful
estimates of the impedance tensor. To derive an image of the subsurface resistivity distribution a
three dimensional inverse modelling of the impedance tensor estimates has been applied.