DIAGNOSTICS OF META-INSTABLE STATE OF SEISMICALLY ACTIVE FAULT

Based on the results of a laboratory simulation of the seismic fault reactivation by “stick-slip” process, it was shown that the system of two blocks just before an impulse offset goes through the meta-instable dynamic state, with early and late stages of meta-instability [Ma et al., 2012]. In the first stage the offset begins in slow stationary mode with slow stresses relaxation on contact between blocks. In the second stage of the “accelerated synergies” strain rate increases and, subsequently, the deformation process through a process of self-organization came to dynamic impulse offset. The experimental results were used for interpretation of the results of spectral analysis of the deformation monitoring data. The data were held within the southern part ofLakeBaikal, where Kultuk earthquake (27.08.2008, Ms=6.1). took place. Its epicenter was located in the South end zone of the main Sayan fault. Monitoring of deformations of rocks was carried out from April to November2008 in tunnel, located at30 km from the epicenter of the earthquake. The time series data was divided into month periods and then the periods were processed by the method of spectral analysis. The results showed that before the earthquake has ordered view spectrogram, whereas in other time intervals, both before and after the earthquake such orderliness in spectrograms is missing. An ordered view spectrograms for deformation monitoring data can be interpreted as a consequence of the self-organiza­tion of deformation process in the transition of seismically active fault into meta-unstable before the Kultuk earthquake.

1. Bak P., Tang C., 1989. Earthquakes as a self-organized critical phenomenon. Journal of Geophysical Research: Solid Earth 94 (B11), 15635–15637. https://doi.org/10.1029/JB094iB11p15635.

2. Bornyakov S.A., Miroshnichenko A.I., Salko D.V., 2016. Diagnostics of the preseismogenic state of heterogeneous media according to deformation monitoring data. Doklady Earth Sciences 468 (1), 481–484. https://doi.org/10.1134/S1028334X16050032.

3. Brace W.F., Byerlee J.D., 1966. Stick-slip as a mechanism for earthquakes. Science 153 (3739), 990–992. https://doi.org/10.1126/science.153.3739.990.

4. Chelidze T., Matcharashvili T., Gogiashvili J., Lursmanashvili O., Devidze M., 2005. Phase synchronization of slip in la¬boratory slider system. Nonlinear Processes in Geophysics 12 (2), 163–170. https://doi.org/10.5194/npg-12-163-2005.

5. Ciliberto S., Laroche C., 1994. Experimental evidence of self organized criticality in the stick-slip dynamics of two rough elastic surfaces. Journal de Physique 4 (2), 223–235. https://doi.org/10.1051/jp1:1994134.

6. Feder H.J.S., Feder J., 1991. Self-organized criticality in a stick-slip process. Physical Review Letters 66 (20), 2669–2672. https://doi.org/10.1103/PhysRevLett.66.2669.

7. Haken H., 1977. Synergetics: An Introduction. Springer, Berlin – Heidelberg – New York, 325 p.

8. Kondepudi D., Prigozhin I., 1998. Modern Thermodynamics: From Heat Engines to Dissipative Structures: Second Edition. John Wiley & Sons, Oxford, 506 p.

9. Lomb N.R., 1976. Least-squares frequency analysis of unequally spaced data. Astrophysics and Space Science 39 (2), 447–462. https://doi.org/10.1007/BF00648343.

10. Lyubushin A.A., 2012. Prediction of the Great Japanese earthquake. Priroda (Nature) (8), 23–33 (in Russian) [Любу-шин А.А. Прогноз Великого Японского землетрясения // Природа. 2012. № 8. С. 23–33].

11. Ma J., Guo Y., Sherman S.I., 2014. Accelerated synergism along a fault: A possible indicator for an impending major earthquake. Geodynamics & Tectonophysics 5 (2), 387–399. https://doi.org/10.5800/GT-2014-5-2-0134.

12. Ma J., Sherman S.I., Guo Y.S., 2012. Identification of meta-instable stress state based on experimental study of evolution of the temperature field during stick-slip instability on a 5 bending fault. Science China Earth Sciences 55 (6), 869–881. https://doi.org/10.1007/s11430-012-4423-2.

13. Myachkin V.I., Kostrov B.V., Sobolev G.A., Shamina O.G., 1975. Fundamentals of the physics of earthquake focus and forerunners. In: M.A. Sadovsky (Ed.), Physics of earthquake focus. Nauka, Moscow, p. 6–29 (in Russian) [Мячкин В.И., Костров Б.В., Соболев Г.А., Шамина О.Г. Основы физики очага и предвестники землетрясений // Физика очага землетрясения / Ред. М.А. Садовский. М.: Наука, 1975. С. 6–29].

14. Olami Z., Feder H.J.S., Christensen K., 1992. Self-organized criticality in a continuous, nonconservative cellular automaton modeling earthquakes. Physical Review Letters 68 (8), 1244–1247. https://doi.org/10.1103/PhysRevLett.68.1244.

15. Press W.H., Teukolsky S.A., Vetterling W.T., Flannery B.P., 2007. Numerical Recipes: The Art of Scientific Computing. 3rd Edition. Cambridge University Press, London, 1256 p.

16. Ruzhich V.V., Psakhie S.G., Chernykh E.N., Bornyakov S.A., Granin N.G., 2009. Deformation and seismic effects in the ice cover of Lake Baikal. Russian Geology and Geophysics 50 (3), 214–221. https://doi.org/10.1016/j.rgg.2008.08.005.

17. Savransky D., 2004. Lomb (Lomb-Scargle) Periodogram. Mathlab Central. Available from: http://www.mathworks.com/matlabcentral/fileexchange/20004-lomb--lomb-scargle--periodogram (last accessed October 24, 2017).

18. Scargle J.D., 1982. Studies in astronomical time series analysis. II – Statistical aspects of spectral analysis of unevenly spaced data. The Astrophysical Journal 263, 835–853.

19. Scargle J.D., 1989. Studies in astronomical time series analysis. III – Fourier transforms, autocorrelation functions, and cross-correlation functions of unevenly spaced data. The Astrophysical Journal 343, 874–887.

20. Sobolev G.A., Ponomarev A.V., 2003. Physics of Earthquakes and Precursors. MAIK “Nauka”, Moscow, 270 p. (in Russian) [Соболев Г.А., Пономарев А.В. Физика землетрясений и предвестники. М.: Наука, 2003. 270 с.].

21. Vityazev V.V., 2001. Analysis of Irregular Time Series. St. Petersburg State University, St. Petersburg, 67 p. (in Russian) [Витязев В.В. Анализ неравномерных временных рядов. СПб.: СПбГУ, 67 с.].

22. Vstovsky G.V., Bornyakov S.A., 2010. First experience of seismodeformation monitoring of Baikal rift zone (by the example of South-Baikal earthquake of 27 August 2008). Natural Hazards and Earth System Sciences 10 (4), 667–672. https://doi.org/10.5194/nhess-10-667-2010.

23. Zhang L., Feng J., Li B., Chi J., Yang Z., Shi X., 1992. The oscillation during instability of rock body and the multilateral faulting traces. Seismology & Geology 14 (1), 1–9.