The area around Nový Kostel/NW-Bohemia is part of the geodynamically active Variscan orogenic belt in Europe, and experiences repeated occurrence of intra-plate earthquake swarms and is characterized by numerous mineral springs and CO2 emissions. These phenomena are usually related to volcanic activity. To better understand the underlying processes, the Eger rift and the Cheb Basin are favored as a possible location for several scientific drillings.

Magnetotelluric (MT) data sense the electrical resistivity of the Earth, a physical parameter that is particularly sensitive to the presence of low-resistivity phases such as aqueous fluids, partial melts or metallic compounds. Fluid phases have electrical resistivities orders of magnitude lower than that of the rock matrix, and relatively small amount of fluids, when interconnected, can thus decrease bulk rock resistivity by several orders of magnitude. Measurements of electrical resistivity can therefore be used to constrain the volume of subsurface fluids, their interconnectivity and the rheology of the crust and mantle.

Time frame

• 1/2015 - 12/2018

Funding

• DFG (WE2938/10-1)

Principal Investigators

• PD Dr. Ute Weckmann
• Dr. Josef Pek

Personnel

• Basel Aleid (GFZ Potsdam)
• Dr. Gerard Munoz (formerly GFZ Potsdam)
• Paula Rulff (formerly GFZ Potsdam)

Cooperations

• Institute of Geophysics of the Czech Academy of Sciences, Prague
• Uppsala University

Methods & Equipment

• MT (Metronix induction coils, Ag-AgCl elektrods, S.P.A.M. IV data logger)
• RMT (MK5SM25 und EnviroMT)

Publications/Results

• Muñoz, G., Weckmann, U., Pek, J., Kováčiková, S., Klanica, R. (2018): Regional two-dimensional magnetotelluric profile in West Bohemia/Vogtland reveals deep conductive channel into the earthquake swarm region. - Tectonophysics, 727, 1-11. doi:10.1016/j.tecto.2018.01.012

Acknowledgements

We would like to thank

• the Deutsche Forschungsgemeinschaft (DFG) for project funding [WE 2938/10-1]
• the Geophysical Instrument Pool Potsdam for providing the instruments
• farmers for giving us access 
• Světlana Kováčiková, Radek Klanica, Manfred Schüler, Yasmin Sanz, Josef Telecky, Laura Schmidt, Gregor Willkommen and Students from Germany and the Czech Republic for their help during the MT and RMT experiments