Application of the matrix method in inverse problems using real seismograms

2013;
: pp. 265 - 267
https://doi.org/10.23939/jgd2013.02.265
Received: July 30, 2013
1
Carpathian Branch of Subbotin Institute of Geophysics of NAS of Ukraine
2
Carpathian Branch of Subbotin Institute of Geophysics of NAS of Ukraine
3
Carpathian Branch of Subbotin Institute of Geophysics of NAS of Ukraine
4
Carpathian Branch of Subbotin Institute of Geophysics of NAS of Ukraine

Purpose. The aim of the research is to develop a methodology for determining local earthquake mechanisms which are registered by a limited number of stations, using real records. Methodology. Methods of the inverse problem solving for determining earthquake parameters are based on the results obtained by direct problem of seismic wave propagation in an anisotropic media using the method of Thomson-Haskell. Analytical and numerical methods have been developed to determine the orientation angles of the fault plane using spectra of real seismic records at stations that have recorded seismic events and anisotropic velocity model. To determine the focal mechanisms a graphic method is also used which is based on first arrivals of P-waves. Results. The results of the inverse problem solving for the earthquake that took place at 24.10.2012, 03:13:40.501 (φ=48.1676˚, λ=23.6525˚, h=5 km) are shown. The comparison of earthquake mechanisms, which were reconstructed with the graphical method as well as with the plane of rupture orientation angles which were obtained through the inverse problem solution, has been carried out. A comparative analysis of real and synthetic seismograms constructed from the obtained seismic moment tensor have been done. Originality. For the first time the method of inverse problem solving for the earthquake parameters, in the case of an anisotropic medium, using real seismic records is developed. Approbation of the presented method is done by comparing real seismograms to synthetic ones which are calculated for the obtained moment tensor. Practical significance. The received solutions are the basis for the analysis of source parameters that are important in many problems of seismology. The developed method of determining the orientation angles of the fault plane based on the direct dynamic problem solutions and real seismic records of events taking place in the Transcarpathian region is very important in the study of the seismicity of Ukraine.

1. Chapman C. H. Fundamentals of seismic wave propagation. Cambridge: Cambridge university press, 2004. 608 p.
https://doi.org/10.1017/CBO9780511616877
2. Christensen N. I., Salisbury M. H. Seismic anisotropy in the oceanic upper mantle: evidence from the Bay of Islands ophiolite complex. J. geophys. Res., 1979 no. 84, рp. 4601-4610.
https://doi.org/10.1029/JB084iB09p04601
3. Crampin S. A review of wave motion in anisotropic and cracked elastic-media. Wave motion, 1981 no. 3, pp. 343-391.
https://doi.org/10.1016/0165-2125(81)90026-3
4. Malytskyy D.V, Pavlova A.Yu., Poshirennja sejsmіchnih hvil' v anіzotropnih seredovishhah. Prjama zadacha - І [Propagation of the seismic waves in the anisotropic media. Direct problem - I]. Geoіnformatika [Geoіnformatics], 2013, vol. 45, no. 1, pp. 25-30.