Geoinformatika 2017; 3(63) : 43-47 (in Ukrainian)

EFFECT OF MAGMATIC ROCKS VYGORLAT-HUTYN VOLCANIC RIDGE ON PROPAGATION TIME OF SEISMIC WAVES

E. Kozlovskyy, D. Malytskyy, A. Parfeniuk, O. Grytsai, V. Tymoshchuk, I. Yarema, O. Astashkina, М. Makhnitskyy

Carpathian Branch of the Subbotin Institute of Geophysics, NAS Ukraine, 3B, Naukova Str., Lviv, 79060, Ukraine, e-mail: dmalytskyy@gmail.com, kem2406@gmail.com, susyinet@gmail.com

The purpose of this work is to clarify the velocity of seismic waves propagation in the first and second layers for seismic events recorded by the seismic stations “Mukachevе”, “Brid” and “Nyzhnie Selysche” for the period from 2002 through to 2013 with the influence of magmatic rocks of the Vygorlat-Hutyn volcanic ridge. The investigation is important in determining and specifying the focal mechanisms of earthquakes.
Methodology. To determine the focal mechanisms of the earthquake, use is commonly made of the standard velocity model for a particular Transcarpathian seismic stations. However, the value of the velocity of seismic waves propaga­tion in the medium has a significant impact on the calculation of the take-off angle of seismic wave, which is one of the major parameters for determining the focal mechanism of earthquakes. Therefore, to clarify the earthquake focal mechanism it is necessary to use a non-standard velocity model and calculate the velocity of the seismic waves propagation in layers for each seismic event, as they can vary widely depending on the azimuth of the stations and the take-off angles of direct P-wave from the source to station.
Findings. The example of the events that took place 17.10.2006. (φ = 48,61˚ N, λ = 22,46˚ E, ε = 24140 m, h = 3300 m) shows that the impact of magmatic rocks Vygorlat-Hutyn volcanic ridge reduces the propagation time of seismic waves in the sedimentary layer and partially in the basement.
Practical value. To determine the focal mechanism of the earthquake, we are to consider velocity of seismic waves in the layers for each individual case but not the standard velocity model under seismic stations.

Keywords: Vigorlat-Gutinska volcanic ridge, velocity model, time of propagation of the seismic wave, focal mecha­nism of the earthquake.

The full text of papers

References:

1. Kozlovskyy E., Malytskyy D., Pavlova A. The calculation and analysis of azimuthal qi coefficients for seismically active regions Transcarpathian. Geodynamics, 2013, no. 2, pp. 174-176 [in Ukrainian].
2. Malytskyy D., Pavlova A., Grytsai O., Muyla O., Astashkina O., Obidina OMethod of determination of source parameters (point and distributed) based on data of limited number of seismic stations. Geoinformatika, 2016, no. 4, pp. 20-28 [in Ukrainian].
3. Malytskyy D., Muyla O., Pavlova A., Grytsai O., Koval Yu., Obidina O. Fire earthquake: simulation, determination of parameters and usage. Geoinformatics, 2016, no. 1, pp. 1-12 [in Ukrainian].
4. Prykhodko G. The cyclic evolution of the Neogene volcanism and associated mineralization of the southern part of the Mukachevo depression. Geologist of Ukraine, 2004, no. 4, pp. 50-54 [in Russian].
5. Seismological Bulletin of Ukraine (2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013): [under ed. B.G. Pustovitenko]. Sevastopol, NPC “ECOSY-Hydrophysics” [in Russian].

6. Mai P.M., Schorlemmer D., Page M., Ampuero J.-P., Malytskyy D. The Earthquake-Source Inversion Validation (SIV) Project. Seismo. Res. Lett, 2016, no. 87, pp. 690-708.