Purpose. To investigate structure-tectonic and faults features of the central part of the Transcarpathian internal depression and their relations with earthquake epicenters localization and peculiarities of seismic waves spreading on the base of instrumental observations in regime geophysical observatories of the Carpathian geodynamic polygon. Methods and results. The study developed methodology for specification of local earthquake focus depths by means of neuron-network modeling, computer processing and systematization of observation data at the Carpathian geodynamic network and adjusting areas on the basis of recent mapping and graphical information. On the examples of earthquakes registered by the regime geophysical station “Mukachevo”, focal mechanisms of earthquakes were determined using first arrival polarities. Scientific novelty. The research determined the relationships between structural and tectonic features in the central part of the Carpathian backdeep, the recent geodynamics of the region’s basement, peculiarities of seismic waves spreading, and formation of local earthquake focuses. It was stated that the influence of the igneous rocks of the Vyhorlat-Hutyn volcanic ridge significantly reduced the time of seismic waves passing in the sedimentary layer and partly in the basement. To determine a focal mechanism of the earthquake, the velocity of seismic waves in the layers should be taken into account on a case-by-case basis, taking into account the location of seismic stations with respect to deep and surface faults and the impact of volcanic rocks, and not using standard velocity models for seismic stations resulting from the stations that give significant results in calculations of output seismic wave angle and facilitate the selection of nodal surfaces. Practical value. Detailed investigations allow determining characteristics of earthquake epicenters, velocities and direction of seismic waves spreading in accordance with the structure of the basement and sedimentary layer. This will, in turn, provide an opportunity to supplement the data of long-term monitoring of natural and technological hazards in the region.
1. Aki, K., Richards, P.G. (2002). Quantitative seismology. Theory and methods. Sausalito, California: University Science Books, 520 p
2. Dreger, D. S. & Helmberger, D. V. (1993). Determination of source parameters at regional distances with single station or sparse network data. J. Geophys Res., 98, 1162-1179.
3. Hardebeckm, J. L., Shearer, P. M., (2003). Using S/P amplitude ratios to constrain the focal mechanisms of small earthquakes. Bull.seism. Soc.Am., 93, 2432-2444.
4. Hnylko, O. M. (2011). Tectonic zoning of the Carpathians in terms of the terrane tectonics. Section 1: Main units of the Carpathian building. Geodynamics, no. 1 (10), 47-57. (in Ukrainian).
5. Hnylko, O. M. (2012). Tectonic zoning of the Carpathians in terms of the terrane tectonics. Article 2. The flyssch Carpathian - ancient accretionary prism. Geodynamics, 1 (12), 67-78. (in Ukrainian).
6. Kozlovskyy, E., Маlytskyy, D., & Pavlova А. (2014). Neural-network modeling for the problem softemporal specifying of direct P-wave entering and calculating the depth of anearthquake source. Geoinformatics, 3. (in Ukrainian).
7. Kozlovskyy, Е., Маlytskyy, D., Parfenuk, А., Grytsay O., Tymoshchyk, V., Yarema, I., Astashkina, O., & Mahnitskyy M. (2017). Influence of magmatic rocks in the Vigorlat-Gutin volcanic ridge during the seismic waves transition., Geoinformatics, 3(63). (in Ukrainian).
8. Kruglov, S. S., Smirno,v S. E., & Spitkovskaya, S. M. (1985). Geodynamics of the Carpathians. Kyiv: Nauk. opinion. (In Russian).
9. Krupskyy, Yu. (2001). Geodynamic forming conditions and oil-and-gas bearing of the Carpathian and Volyn-Podillya areas of the Ukraine, Kyiv: UkrDHRI. (in Ukrainian).
10. Krylov, N. A. (1988). Map faults and main zones liniamentov southwest of the USSR (the calibration using materials space shooting). (In Russian).
11. Kuznetsova, V. (1978). The study of secular variations of the geomagnetic field. Book: Carpathian geodynamic polygon (In Russian).
12. Maksymchuk, V., Gorodisky, Yu., & Kuznetsova, V. (2001). Dynamics of anomalous magnetic field of the Earth, Lviv: Eurosvit (in Ukrainian).
13. Maksymchuk, V. Yu, Pyrizhok, N. B., Pronyshyn, R. S., & Tymoschuk, V. R. (2014). Peculiarities of Transcarpathians seismisity, Geodynamics, 2 (17). (in Ukrainian).
14. Malytskyy, D., Hrytsai, O., Muyla, O., Kutniv, O., Obidina, O., Astashkina, O., Pavlova, A., & Kozlovskyy, E. (2015) On determining focal mechanismsof earthquakes in the Mediterranean region using graphic method. Geoinformatika 4 (56), 43-51. (in Ukrainian).
15. Malytskyy, D., Pavlova, A., & Hrytsai, O. (2014). Determining the focal mechanisms of the events in the Carpathian region of Ukraine. Geoscientific Instrumentation Methods and Data Systems. ,3, 229-239.
16. Medvedev, A. P. (2015). Geodynamic and geochemical aspects of oil and gas accumulation in oil and gas regions of Ukraine. Institute of Geology and Geochemistry of Combustible Minerals.
17. Melnychuk, M. (1982). About the genetic relationship of seismic processes and tectonics of the Carpathian region. Geophysical journal, 4(2), 34-41. (In Russian).
18. Pronyshyn, R. S., & Kuznecova, V. G. (2011). Relationship of the spatial distribution of seismicity with the tectonic structure of the Transcarpathian depression. Geodynamics. № 2. 254-256. (in Ukrainian).
19. Pronishin, R. S., & Pustovitenko, B. G. (1982). Some aspects of seismic climate and weather in Transcarpathia. Izv. USSR Academy of Sciences. Earth Physics, (10), 74-81.
20. Seghedia, I., Downes, H., Vaselli, O., Szakacs, A., Balogh, K., Pecskay, Z. (2004). Post-collisional Tertiary-Quaternary mafic alkalic magmatism in the Carpathian-Pannonian region: a review. Tectonophysics, 393, 43-62.
21. Seismological bulletin of Ukraine for 2001, 2002, 2003, 2004. red. B. G. Pustovitenko. S. I. Subbotin Institut of Geophisics NAN Ukrain, Simferopol', 2005, 2006, 2007, 2008.
22. Seismological bulletin of Ukraine for 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. Sevastopol: NPC Jekosi-Gidrofizika, 2007, 2008, 2009, 2010, 2011, 2012, 2013.
23. Starostenko, V., Janik, T., Kolomiyets, K., Czuba, W., Środa, P., Grad, M., ... & Artemieva, I. M. (2013). Seismic velocity model of the crust and upper mantle along profile PANCAKE across the Carpathians between the Pannonian Basin and the East European Craton. Tectonophysics, 608, 1049-1072.