Models for Area Seismic Source Definition and Parameterization for Georgia and the Surrounding Region

Authors

  • Otar Sh. Varazanashvili
  • Nino S. Tsereteli

Keywords:

Georgia, seismic source, seismic hazard, active faults, magnitude-frequency distribution, earthquake depth.

Abstract

Models of area seismic source (ASSs) are the basic and most important inputs required for Probabilistic Seismic Hazard Analysis (PSHA), because on them mainly depends the reliability of the final results of seismic hazard assessment. Determinations of these models include the delineation of ASSs and their parameterization. In practical applications, when clear procedures for constructing ASSs do not exist, this leads to large variations in the computed hazard.

In the Caucasus, where active faults are clearly defined and parameterized, and seismicity is relatively well documented, a method of ASS delineation is used, which was developed by us. The procedure for constructing ASSs is based on the delineation, along the active fault, of an area with a certain width. The width of the ASS is dependent from fault plane dip and width, from the thickness of seismically active layers and from geometrical sizes earthquake source. ASSs asymmetry relative to the axial line of the fault is a characteristic feature of these construction. On the basis of these method, ASSs were delineated for Georgia and the surrounding region.

Each ASS is expressed by a set of parameters that will represent the basic input for seismic hazard assessment. Mmax assessments were implemented on the basis of three seismological and two geological methods. The magnitude-frequency distribution b parameter was calculated for 16 generalized tectonic units, for which seismic statistics were quite complete, and the a parameter was determined for each ASS. A study of the depth distribution of earthquakes showed that seismicity in this region is mainly shallow.

References

Adamia Sh., Mumladze N., Sadradze N., Tsereteli E., Tsereteli N., Varazanashvili O. Late Cenozoic tectonics and geodynamics of Georgia (SW Caucasus). Georgian International Journal of Science and Technology, vol. 1(1), 2008, 77-107.

Adamia Sh., Zakariadze G., Chkhotua T., Sadradze N., Tsereteli N., Chabukiani A., Gvencadze A. Geology of the Caucasus: a review. Turkish Journal of Earth Science, vol. 20(5), 2011, 489-544.

Aleshin A. S., Barkhatov I. I., Nesmeyanov S. A., Sevostyanov V. V., Fedorov S. A., Shmidt G. A. Tectonicheskie razlomi na uchastkakh seismicheskogo microraionirovania. Moscow: Pub. House Nauka, 1982.

Caputo M., Gamkrelidze I., Malvezzi V., Sgrigna V., Shengelaia G., Zilpimiani, D. Geostructural basis and geophysical investigations for the seismic hazard assessment and prediction in the Caucasus. Il Nuovo Cimento, 23C(2), 2000, 191-215.

Danciu L., Şeşetyan K., Demircioglu M., Gülen L., Zare M., Basili R., Elias A., Adamia Sh., Tsereteli N., Yalçın H., Utkucu M., Asif Khan M., Sayab M., Hessami Kh., Rovida A. N., Stucchi M., Burg J. P., Karakhanian A., Babayan H., Avanesyan M., Mammadli T., Al-Qaryouti M., Kalafat D., Varazanashvili O., Erdik M., Giardini D. The 2014 Earthquake Model of the Middle East: seismogenic sources. Bulletin of Earthquake Engineering, vol. 16(8), 2018, 3465–3496.

DePolo C. M., Clark D. G., Slemmons D. B., Ramelli A. R. Historical surface faulting in the Basin and Range province, western North America: implications for fault segmentation. Journal of Structural Geology, vol.13(2), 1991, 123-136.

Gardner J.K., Knopoff L. Is the sequence of earthquakes in southern California, with aftershocks removed, Poissonian? Bull. Seismol. Soc. Am., 1974, 64(5),1363–1367.

Gupta I. D. Probabilistic seismic hazard analysis method for mapping of spectral amplitudes and other design-specific quantities to estimate the earthquake effects on man-made structures. ISET Journal of Earthquake Technology, vol. 44(1), 2007, 127–167.

Pailoplee S., Choowong M. Earthquake frequency-magnitude distribution and fractal dimension in mainland Southeast Asia. Earth, Planets and Space, vol. 66(8), 2014, 1-10.

Pizzi A., Galadini F. Pre-existing cross-structures and active fault segmentation in the northern-central Apennines (Italy). Tectonophysics, vol. 476(1-2), 2009, 304–319.

Shebalin N. V., Trifonov V. G., Kozhurin A. I., Ulomov V. I., Tatevossian R. E., Ioffe A. I. A unified seismotectonic zonation of Northen Eurasia. Journal of Earthquake Prediction Research, v. 8, 2000, 8-31.

Tibaldi A., Tsereteli N., Varazanashvili O., Babayev G., Barth A., Bonali F. L., Russo E., Kadirov F., Yetirmishli G., Kazimova S., Mumladze T. Active stress field and fault kinematics of the Greater Caucasus. Journal of Asian Earth Sciences, 2019, https://doi.org/10.1016/j.jseaes.2019.104108

Tsereteli N., Varazanashvili O., Kupradze M., Kvavadze N., Gogoladze Z. Seismic catalog for Georgia. Journal of Georgian Geophysical Society 16a, 2016, 62-69.

Ulomov V. I. Focal zones of earthquakes modeled in terms of the lattice regularization. Izvestiya, Physics of the Solid Earth, vol. 34(9), 1998, 717–733.

Varazanashvili O., Tsereteli N., Bonali F. L., Arabidze V., Russo E., Mariotto F. P, Gogoladze Z., Tibaldi A., Kvavadze N., Oppizzi P. GeoInt: the first macroseismic intensity database for the Republic of Georgia. Journal of Seismology, 22(3), 2018, 625-667.

Weatherill G., Burton P. W. Delineation of shallow seismic source zones using K-means cluster analysis, with application to the Aegean region. Geophysical Journal International, vol. 176(2), 2009, 565-588.

Weichert D.H. Estimation of the earthquake recurrence parameters for unequal observation periods fordifferent magnitudes. Bull. Seismol. Soc. Am. 70(4), 1980, 1337-1346.

Wells D. L., Coppersmith K. J. New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bulletin of the Seismological Society of America, vol. 84(4), 1994, 974–1002.

Wheeler R. L. Methods of Mmax Estimation East of the Rocky Mountains. U.S. Geological Survey Open-File Report 2009-1018, 2009, 44 p.

Zare M., Amini H., Yazdi P., Sesetyan K.., Demircioglu M.B., Kalafat D., Erdik M., Giardini D., Khan M.A., Tsereteli N. Recent developments of the Middle East catalog. Journal of Seismology, 18(4), 2014, 749-772.

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How to Cite

Varazanashvili, O. S., & Tsereteli, N. S. (2020). Models for Area Seismic Source Definition and Parameterization for Georgia and the Surrounding Region. JOURNAL OF THE GEORGIAN GEOPHYSICAL SOCIETY, 23(1). Retrieved from https://openjournals.ge/index.php/GGS/article/view/2648