STRESS STATE MODELING AND GEODYNAMIC ZONING IN SEISMICALLY ACTIVE REGIONS

Stress state of epicentral area before and after earthquake (after formation of major fracture) is modeled. The employed software system allows 2D (plain-strain deformation) modeling of stress state of heterogeneous geological medium with a system of tectonic faults. The faults were modeled as extended zones of loosened geomaterial with elastic modulus essentially lower than the elastic modulus of the host medium. The modeling was carried out using the structure and tectonics layout of the Erzincan earthquake area, including geology and geophysics of tectonics and seismicity in this region. The strong Erzincan Earthquake (Ms 6.8) occurred on March 13, 1992 in Turkey, in the zone of the North-Anatolian Fault with the hypocenter at the depth of 10 km. Two days after that, a strong Ms 5.8 aftershock took place. All in all, more than 300 aftershocks were recorded in the epicentral area. High-density concentration of aftershocks is observed in the zone of the North-Anatolian Fault intersection with adjacent tectonic faults. The results of modeling stress state in the zone 60×60 km before and after the earthquake are analyzed. It is shown that zones of high intensity and peak values of shear stresses conform with the zone of highdensity concentration of aftershocks. The strongest aftershocks with M > 3.7 localize in the zone of maximally relaxed intensity of stresses after formation of the fault. Stress relaxation after the fault formation promotes relief of “secular” accumulated tectonic stresses during subsequent series of aftershocks. These results are useful in deterministic approach to assessment of seismic hazard and in geophysical studies aimed at prediction of strong continental crust earthquakes.


This study was supported by the Geophysical Center of the Russian Academy of Sciences within the framework of the state contract on topic No. 0145-2016-004.

Keywords

Modeling, stress state, earthquake, earthquake foci, faults, tectonics.

Issue number: 8
Year: 2018
ISBN:
UDK: 550.34.06; 550.34.01
DOI: 10.25018/0236-1493-2018-8-0-123-132
Authors: Morozov V. N., Manevitch A. I., Tatarinov V. N.

About authors: Morozov V.N., Doctor of Technical Sciences, Professor, Chief Researcher, e-mail: morozov@gcras.ru, Manevitch A.I., Junior Researcher, e-mail: ai.manevich@yandex.ru, Tatarinov V.N., Doctor of Technical Sciences, Head of Laboratory, e-mail: v.tatarinov@gcras.ru, Geophysical Center of Russian Academy of Sciences, 119296, Moscow, Russia.

REFERENCES:

1. Morozov V. N., Kolesnikov I. YU., Belov S. V., Tatarinov V. N. Napryazhenno-deformirovannoe sostoyanie Nizhnekanskogo massiva rayona vozmozhnogo zakhoroneniya radioaktivnykh otkhodov [Stress state of the Nizhnekansky granitoid massif area—zone of possible radioactive waste disposal]. Geoekologiya. 2008, no 3, pp. 232—243. [In Russ].

2. Morozov V. N., Kolesnikov I. Yu., Tatarinov V. N. Modelirovanie urovney opasnosti napryazhennodeformirovannogo sostoyaniya v strukturnykh blokakh Nizhnekanskogo granitoidnogo massiva (k vyboru uchastkov zakhoroneniya radioaktivnykh otkhodov) [Modeling stress state hazard levels in structural blocks

of the Nizhnekansky granitoid massif (to select areas for radioactive waste disposal)]. Geoekologiya. 2011, no 6, pp. 524—542. [In Russ].

3. Morozov V. N., Kolesnikov I. Yu., Tatarinov V. N. Modeling the hazard levels of stress-strain state in structural blocks in Nizhnekanskii granitoid massif for selecting nuclear waste disposal sites. Water Resources, 2012, Vol. 39, Issue 7, pp. 756—769.

4. Morozov V. N., Tatarinov V. N. Tectonic processes development with time in the areas of HLW disposal from expert assessment to prognosis. Int. Nuclear Energy science and Technology, 2006. Vol. 2. No, 1/2. Pp. 65—74.

5. Morozov V. N., Manevich A. I. Modelirovanie napryazhenno-deformirovannogo sostoyaniya epitsentral'nogo rayona zemletryaseniya 26.01.2001 g., M = 6.9 (Indiya) [Modeling stress state in the epicentral area of the earthquake on Jan 26, 2001 M = 6.9, India]. Geofizicheskie issledovaniya. 2016, vol. 17, no 4, pp. 23—36. DOI: 10.21455/gr2016.4-2. [In Russ].

6. Reddy C. D., Sunil P. S. Post-seismic crustal deformation and strain rate in Bhuj region, western India, after the 2001 January 26 earthquake. Geop. J. Int., 2008, Vol. 172, Issue 2, pp. 593—606. DOI: 10.1111/j.1365—246X.2007.03641.x.

7. Sinvhal A., Bose P. R., Prakash V., A. Bose, Saraf A. K., Sinvhal H. Isoseismals for the Kutch earthquake of 26th January 2001. Journal of Earth System Science. 2003, Vol. 112, Issue 3, pp. 375—383.

8. Narula P. I., Chaubey S. K. Macroseismic surveys for the Bhui (India) earthquake. 2004.

9. Narsaiah Rapolu, Prantik Mandal. Source parameters of the 2001 Mw 7.7 Bhuj earthquake, Gujarat, India, aftershock sequence. Journal of the Geological Society of India. May 2014, Vol. 83, Issue 5, pp. 517—531.

10. Kayal J. R., Mukhopadhyay S. Seismotectonics of the 2001 Bhuj earthquake (Mw 7.7) in western India: Constraints from aftershocks. J. Ind. Geophys. Union, 2006, Vol. 10, No 1, pp. 45—57.

11. Shebalin N. V., Dorbat K., Tatevosyan R. E. Razmery, forma i polozhenie ochaga Spitakskogo zemletryaseniya: Aftershoki i makroseysmika [Size, shape and location of the Spitak earthquake focus: Aftershocks and microseismicity], Izvestiya AN SSSR. Fizika Zemli, 1991, no 11, pp. 18—26. [In Russ].

12. Ben'off G. Mekhanizm i kharakteristiki deformatsiy razryva Uayt-Vulf, vyyavlennye pri izuchenii posledovatel'nosti aftershokov [Mechanism and characteristics of the White Wolf Fault deformation revealed in the analysis of sequence of aftershocks]. Slabye zemletryaseniya. Moscow, 1961, pp. 211—219. [In Russ].

Подписка на рассылку

Раз в месяц Вы будете получать информацию о новом номере журнала, новых книгах издательства, а также о конференциях, форумах и других профессиональных мероприятиях.