Institute of Geophysics of the CAS, v. v. i.


West Bohemia Volcanism

The volcanic structures of the maar Mýtina / the scoria cone Železná hůrka and the active magmatic CO2-degassing zone Milhostov - Hartoušov in the Western Eger Rift (Czech Republic)


Project origin
Based on volcanological investigation and inspection of terrain morphology, the scouting gravity/magnetic survey revealed impressive anomalies indicating possible existence of a maar-diatreme volcanic structure near the Železná hůrka Quaternary scoria cone volcano near Mýtina, West Bohemia (Mrlina et al., 2007). The follow-up detailed survey showed a gravity low and magnetic high (see figure below) which gave reasoning to exploratory drilling of a shallow well (Mrlina et al., 2009). Lake sediments underlain by volcanic breccia were identified from the well core.

The Mytina maar structure is located south of the unique earthquake swarm zone of West Bohemia and the active magmatic CO2 degassing zone Milhostov – Hartoušov driven by magmatic intrusion processes. The volcanic and degassing sites form a natural laboratory, which is unique throughout Central and Western Europe.



Project goals:

1) investigating the internal structure of the Mytina maar, as well as its surroundings in order to reconstruct the palaeovolcanic evolution of the area, based on geophysical surveying (gravimetry, geomagnetics, geoelectrics)

2) study of geologic composition of the CO2 degassing zone Milhostov – Hartoušov and the assumed vents

3) tectonic pre-disposition of both sites

4) evaluation of the potential of future phreatomagmatic eruptions within the area

Principal Investigator from IG ASCR
J.Mrlina (Institute of Geophysics, Academy of Science, Prague, Czech Republic)

Co-workers from Czech Republic
M.Seidl, V.Polák, T.Bayer (Institute of Geophysics, Academy of Science, Prague, Czech Republic)
V.Cajz (Institute of Geology, Academy of Science, Prague, Czech Republic)

C.Flechsig, J.Heinicke (University of Leipzig, Institute of Geophysics and Geology, Germany)
H.Kämpf, T.Nickschick (GFZ Potsdam, Germany)

German Research Foundation, DFG

Mrlina, J., Kämpf, H., Geissler, W.H., van den Boogart, P. (2007): Assumed Quaternary maar structure at the Czech/German boundary between Mýtina and Neualbenreuth (western Eger Rift, Central Europe): geophysical, petrochemical and geochronological indications  – Z. geol. Wiss., 35, 4-5: 213-230.

Mrlina, J., Kämpf, H., Kroner, C., Mingram, J., Stebich, M.,  Brauer, A., Geissler, W.H., Kallmeyer, J., Matthes, H. and  Seidl, M. (2009): Discovery of the first Quaternary maar in the Bohemian Massif, Central Europe, based on combined geophysical and geological surveys. – J. Volc. Geoth. Res., 182, 97-112.