Geology of the area:
The Bükk Mts. is situated NW to Mályi. The Mesozoic rocks, which form the main mass of the Bükk Mts. and are still on the surface in the mountain, have been pushed down by Eocene-Oligocene structural movements in the area south of the mountain (Hevesi A. 2002; Pentelényi L. 2002). These strata are overlayed by marine and coastal Paleogene sediments in varying extent and thicknesses. Explosive volcanic activity during the Miocene produced pyroclastic mudstone and tuff layers, sometimes up to the thickness of 2000 ft (700 m), which is extended in a NE-SW strike direction along with a nearly 50 km long and 10 km wide band on the Bükk Foreland (Lukács R. et al. 2018). Marine, lacustrine and fluvial sediments built up in the late Miocene from alternating clayey and sandy layers (Less Gy. et al. 2002).
The actuality of the research:
In the Bükk Foreland Area, previous researches have identified 11 different deformation stages from Paleogene to recent (Petrik, 2016). The Vatta-Maklár Trough forms a considerable part of the area in the subsurface, which is a sinistral Miocene pull-apart basin, where the strike of the faults are ENE-WSW or NE-SW (figure 1). The recent activity of the structures of the area is also proved by recent earthquakes. In the vicinity of the faults to the west of Mályi, which are one of the key points of our field camp and which are in the northeastern border of the Vatta-Maklár Trough, nine earthquakes with magnitudes of 1-3.3 have been recorded since 2003 by the equipment of the Kövesligethy Radó Seismological Observatory (Tóth et al., 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018). The activity of these faults is verified by sinuosity changes (Pecsmány, 2020).
Another important aspect regarding the faults is geothermics, which is a significant and relevant, „hot” topic in this region. The construction of a geothermal system based on the catchment of the Bükk thermal karst has begun in 2010. In this system, 2 production wells were drilled and put into operation in Mályi, and 3 injection wells in the neighboring Kistokaj. More than 200 °F (90 °C) of thermal water is produced through the wells from the fault system that forms the southern edge of the Bükk Mts. This water abstraction and reinjection for heating purposes provides more than 50 % of the energy demand of the district heating service in Miskolc, and with a total heat capacity of 60 MWt, it is currently the largest geothermal heating system in Hungary. Thus, it can be seen that fault detection in this area can be of paramount importance.
The task:
As can be seen, the structures of the Bükk Foreland Area are not only important and interesting from the geological point of view, but the results obtained from more detailed research can also be useful for a wider audience. Since the faults also show recent activity, this allows us to carry out near-surface geophysical measurements. Using geoelectric and seismic methods, we will precisely locate the position of the faults.
Map of the young geological deformations in the research area. Modified after Wórum et al., 2020.
References:
Hevesi A. (2002). A Bükk hegység földrajzi helyzete, kialakulása, éghajlata (Geographical position, formation and climate of the Bükk Mountains) – In: Baráz Cs. (eds.): A Bükki Nemzeti Park. Hegyek, erdők, emberek (The Bükk National Park. Mountains, Forests, Humans). Bükk National Park Directorate, Eger, Hungary, pp. 15–22.
Less Gy., Gulácsi Z., Kovács S., Pelikán P., Pentelényi L., Rezessy A. & Sásdi L. (2002). A Bükkhegység földtani térképe (Geological map of the Bükk Mountains). Geological Institute of Hungary.
Lukács, R., Harangi, Sz., Guillong, M., Bachmann, O., Fodor, L., Buret, Y., Dunkl, I., Sliwinski, J., von Quadt, A., Peytcheva, I. & Zimmerer, M. (2018). Early to Mid-Miocene syn-extensional massive silicic volcanism in the Pannonian Basin (East-Central Europe): Eruption chronology, correlation potential and geodynamic implications. Earth-Science Reviews, 179. pp. 1–19.
Pentelényi L. (2002). A Bükkalja, I. Földtani vázlat (Bükk foreland, I. Geological sketch) – In: Baráz Cs. (2002) (eds.): A Bükki Nemzeti Park. Hegyek, erdők, emberek (The Bükk National Park. Mountains, Forests, Humans). Bükk National Park Directorate, Eger, Hungary, pp. 205–216.
Petrik A. (2016). A Bükk déli előterének kainozoos szerkezetalakulása (Cenozoic structural evolution of the southern Bükk foreland). PhD Thesis. Eötvös Loránd Univeristy, Dept. of Applied and General Geology, Budapest. 264 p.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2004). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2003, GeoRisk - MTA GGKI, Budapest, p. 136.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2005). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2004, GeoRisk - MTA GGKI, Budapest, p. 94.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2006). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2005, GeoRisk - MTA GGKI, Budapest, p. 80.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2007). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2006, GeoRisk - MTA GGKI, Budapest, p. 80.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2008). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2007, GeoRisk - MTA GGKI, Budapest, p. 76.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2009). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2008, GeoRisk - MTA GGKI, Budapest, p. 98.
Tóth L., Mónus P., Zsíros T., Bus Z., Kiszely M. & Czifra T., (2010). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2009, GeoRisk - MTA GGKI, Budapest, p. 92.
Tóth L., Mónus P., Zsíros T., Kiszely M. & Czifra T., (2011). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2010, GeoRisk - MTA GGKI, Budapest, p. 140.
Tóth L., Mónus P., Zsíros T., Kiszely M. & Czifra T., (2012). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2011, GeoRisk, Budapest, p. 158.
Tóth L., Mónus P., Zsíros T., Kiszely M. & Czifra T., (2013). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2012, GeoRisk, Budapest, p. 88.
Tóth L., Mónus P. & Kiszely M. (2014). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2013, GeoRisk, Budapest, p. 136.
Tóth L., Mónus P. & Kiszely M. (2015). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2014, GeoRisk, Budapest, p. 140.
Tóth L., Mónus P. & Kiszely M. (2016). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2015, GeoRisk, Budapest, p. 132.
Tóth L., Mónus P. & Kiszely M. (2017). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2016, GeoRisk, Budapest, p. 126.
Tóth L., Mónus P., Kiszely M. & Trosts, D. (2018). Magyarországi földrengések évkönyve - Hungarian Earthquake Bulletin - 2017, GeoRisk, Budapest, p. 140.
Wórum, G., Koroknai, B., Koroknai, Zs., Fekete-Németh, V., Kovács, G., Tóth, T. 2020: Young geological deformations in Hungary. Geomega Ltd., Budapest, DOI: 10.17632/dnjt9cmj87.1
