Vera Čejkovska, Lazo Pekevski, Dragana Černih


A b s t r a c t: The 24 April 2002 ML 5.2 Gnjilane earthquake was studied first through inversion of the Sg – Lg wave group displacement amplitude spectrum and P-nodal planes determination. The seismic moment, source spectrum corner frequency and Brune equivalent circular fault surface for this shock were obtained, respectively, as M0 = 6.48·1016 N·m, f0 = 0.59 Hz and Σs,eq = 15.2 km2. The P-nodal planes for the four strongest aftershocks and the distribution of other aftershocks’ epicentres were determined, too, and used in identifying the actual source mechanism of the main shock by a simple method that included also the vertical projections on the Earth’s surface of the main shock Σs,eq with the two main shock P-nodal planes as possible fault planes. It was found that the main shock was caused by a normal right lateral faulting in a plane which struck with an azimuth of 238° and dipped toward NNW under an angle of 22°. This faulting was associated with the shear stressed fault structure along the Pliocene-Quarternary sinking valley of Binačka Morava, and it led to activations of other ruptures as sources of a significant number of aftershocks.


seismic cycle, rupturing, source mechanism, faulting, seismic moment, fault surface, corner frequency

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UNDP/UNESCO Survey of the Seismicity of the Balkan Region, UNESCO, Skopje, 1974.

Dž. Orana, M. Arsovski, V. Mihailov, Seizmotektonske karakteristike SAP Kosovo i njihov značaj za seizmičku rejonizaciju i ocene seizmičkog rizika, Naučno-istraživački projekat, Tehnički fakultet – Priština i Institut za zemljotresno inženjerstvo

i inženjersku seizmologiju – Skopje, 1985.

Љ. Јордановски, Л. Пекевски, В. Чејковска, Д. Черних, Б. Христовски, Н. Василевски, Основни карактеристики на сеизмичноста на територијата на Република Македонија, Универзитет „Св. Кирил и Методиј“, Природно-

математички факултет, Сеизмолошка опсерваторија, Скопје, 1998.

H. F. Reid, The elastic-rebound theory of earthquakes, University of California Publ. Geol. Sci., 6 (1911) 413-444.

Б. В. Костров, Механика очага тектонического землетрясения, Наука, Москва, 1975.

М. А. Садовский, отв. ред., Сб. Физика очага землетрясения, Наука, Москва, 1975.

М. А. Садовский, Б. И. Мячкин, отв. ред.-ы, Сб. Физические процессы в очагах землетрясений, Наука, Москва, 1980.

Дж. Райс, Механика очага землетрясения, Мир, Москва, 1982.

K. Kasahara, Earthquake Mechanics, Cambridge University Press, New York, 1981.

S. Karato, Deformation of Earth Materials. An Introduction to the Rheology of Solid Earth, Cambridge University Press, 2008.

E. Fukuyama, Ed., Fault-zone Properties and Earthquake Rupture Dynamics, Elsevier Academic Press, 2009.

W. H. K Lee, C. M. Valdes, HYP071PC: A personal computer version of the HYPO71 earthquake location program, U. S. Geological Survey Open File Report 85–749, 1985.

UNDP/UNESCO, Tables des temps de propagation des ondes séismiques (Hodochrones) pour la région des Balkans, Manuel d'utilisation, Strasbourg, 1972.

SORM (Seismological Observatory of the Republic of Macedonia), Catalogue of earthquakes occurred in 2002 in the Republic of Macedonia and surrounding areas, Ss. Cyril and Methodius University, Faculty of Natural Sciences and

Mathematics, Seismological Observatory, Skopje, 2002.

SORM (Seismological Observatory of the Republic of Macedonia), Catalogue of earthquakes occurred in 2003 in the Republic of Macedonia and surrounding areas, Ss. Cyril and Methodius University, Faculty of Natural Sciences and

Mathematics, Seismological Observatory, Skopje, 2003.

ISC (International Seismological Centre), International Seismological Centre Bulletin, available from .

R. L. Street, R. B. Herrmann, O. W. Nuttli, Spectral characteristics of the Lg wave generated by Central United States earthquakes, Geophys. J. Roy. Astron. Soc., 41 (1975) 51–63.

R. B. Herrmann, A. Kijko, Modelling some empirical vertical component Lg, Bull. Seismol. Soc. Am., 73 (1983) 157–171.

R. B. Herrmann, An extension of random vibration theory estimates of strong ground motion to large distances, Bull. Seismol. Soc. Am., 75 (1985) 1447–1453.

V. Čejkovska, Empirical relations of seismic moment and earthquake moment magnitude to earthquake local magnitude for the Vardar and West Macedonia seismic zones, Contributions, Sec. Math. Tech. Sci., MANU, XXVII–XXVIII (2006–2007)


L. Pekevski, Q for the territory of Republic of Macedonia, The Albanian Journal of Natural & Technical Sciences, 10 (2001) 81–87.

L. B. Kvamme, R. A. Hansen, H. Bungum, Seismic-source and wave-propagation effects of Lg waves in Scandinavia, Geophys. J. Int., 120 (1995) 525–536.

J. Shi, W. Kim, P. G. Richards, The corner frequencies and stress drops of intraplate earthquakes in the northeastern United States, Bull. Seismol. Soc. Am., 88 (1998) 531–542.

J. N. Brune, Tectonic stress and spectra of seismic shear waves from earthquakes, J. Geophys. Res., 75 (1970) 4997–5009.

J. N. Brune, Correction, J. Geophys. Res., 76 (1971) 5002.

J. Havskov, L. Ottemöller, Seisan: The Earthquake Analysis Software For Windows, Solaris, Linux and Macosx, Version 8.2., Institute of Solid Earth Physics, University of Bergen, Bergen, 2008.

P. A. Reasenberg, D. Oppenheimer, FPFIT, FPPLOT and FPPAGE: FORTRAN computer programs for calculating and displaying earthquake fault-plane solutions, U. S. Geological Survey Open File Report, 85–739, 1985.



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