Abstract
An unusual seismic swarm started on September 23, 2013, close to Galati city, in Izvoarele region (Romania), and lasted until November 12, 2013. 406 earthquakes were recorded during several phases of seismic activity. The strongest events—a magnitude 3.9 earthquake, occurred on September 29, and two ML 3.8 shocks, occurred on October 3 and 4, respectively, were accompanied by specific seismicity bursts. The seismogenic region of the swarm is situated between two main crustal faults, which builds up the primary fault system, oriented SE–NW: New Trotus Fault (at the limit between North Dobrogea and Scythian Platform) to the North and east, and Peceneaga Camena fault (which separates North Dobrogea block from the Moesian Platform) to the South. The epicentral zone belongs to a complex tectonic area, in which a secondary fault system—lying NE–SW, perpendicular to the primary system—is also present. The focal mechanisms show normal faulting, with an important strike-slip component, one of the nodal planes being oriented roughly in a NE–SW direction. The objective of this study is to investigate the seismic swarm recorded in a new seismic area of Romania, near the town Galati in Izvoarele region. We show detailed hypocentral location, focal mechanisms and the correlation between seismicity and tectonic structures.
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References
Aki K, Richards PG (1980) Quantitative seismology, theory and methods, Vol. I and II. W.H. Freeman, San Francisco
Ardeleanu L, Cioflan C (2005) The seismic sequence of 21–22 February 1983 of Ramnicu Sarat: focal mechanism retrieved by genetic algorithm. Rom J Phys 50(5–6):607–614
Båth M (1983) Introduction in seismology. Birkhäuser Verlag, Stuttgart
Enescu D, Popescu E, Radulian M (1996) Source characteristics of the Sinaia (Romania) sequence of May–June 1993. Tectonophysics 261:39–49
Gutenberg B, Richter CF (1944) Frequency of earthquakes in California. Bull Seismol Soc Am 34:185–188
Havskov J, Ottemöller L (2003) SEISAN: The earthquake analysis software for Windows, SOLARIS, LINUX and MACKINTOSH Version 8.0. Manual, Institute of Solid Earth Physics, University of Bergen, Norway
Leever KA, Matenco L, Bertotti G, Cloetingh S, Drijkoningen GG (2006a) Late orogenic vertical movements in the Carpathian Bend Zone—seismic constraints on the transition zone from orogen to foredeep. Basin Res 18:521–545. doi:10.1111/j.1365-2117.2006.00306.x
Leever KA, Bertotti G, Zoetemeijer R, Matenco L, Cloetingh SAPL (2006b) The effects of a lateral variation in lithospheric strength on foredeep evolution: implications for the East Carpathian foredeep. Tectonophysics 421(2006):251–267
Matenco L, Bertotti G, Leever K, Cloetingh S, Schmid SM, Tarapoanca M, Dinu C (2007) Large-scale deformation in a locked collisional boundary: interplay between subsidence and uplift, intraplate stress, and inherited lithospheric structure in the late stage of the SE Carpathians evolution. Tectonics 26(TC4011):2007. doi:10.1029/2006TC001951
Paraschiv D, Cornelia Paraschiv, Cornelia Andrei, Popescu M, Dăneţ N (1983) On the pre-Neogene formations in the North-Dobrogean promontory. Anuarul Inst Geol Geofiz 59:19–27
Popescu E, Radulian M (2001) Ramnicu Sarat (Romania) seismic sequence of December 6–8, 1997: source time function and scaling relations of the earthquake parameters. Rom J Phys 46(7–8):515–530
Popescu E, Radulian M, Popa M (2000) Fractal properties of time, space and size distributions of the Sinaia earthquake sequence of May–June, 1993, St. cerc. Geofizica, tomul 38:29–39, Bucuresti
Radu C, Oncescu MC (1992) The Vrancea (Romania) seismic sequence of August–September 1989. In: Proceedings of XXIInd General Assemblies of ESC, Barcelona 1990
Radulescu DP (1976) Structure de la croute terrestre en Roumanie. Essai’interpre´tation des etudes seismiques profondes. An Inst Geol Geofiz 50:5–36
Radulian M, Mandrescu N, Popescu E, Utale A, Panza G (2000) Characterization of Romanian seismic zones. Pure Appl Geophys 157:57–77
Richter CF (1958) Elementary seismology. Freeman, San Francisco
Snoke JA, Munsey JW, Teague AG, Bollinger GA (1984) A programme for focal mechanism determination by combined use of polarity and SV-P amplitude ratio data, Earthquake Note, 55
Toader VE, Popescu IM, Moldovan IA, Ionescu C (2015) Vrancea seismicity analysis based on cumulative seismic energy, A, U.P.B. Sci Bull Ser A 77(2):297–308
Visarion M, Sandulescu M, Stanica D, Veliciu Ş (1988) Contributions à la connaisance de la structure profonde de la Platforme Moesienne en Roumanie. St. Tehn. Ec., seria D (Geofizică), pp 211–222
Acknowledgments
We would like to thank the three anonymous reviewers for their valuable comments that have contributed to improve the paper. This work was supported partially by a grant of the Romanian National Authority for Scientific Research, CNCS—UEFISCDI, project number PN-II-RU-TE-2012-3-0215; “Nucleu” of the National Plan for Research, Development and Innovation of the Romanian Ministry of National Education. Project PN 09-01 07: Geophysical model of the active fault in Romania; and DARING Project no. 69/2014 supported by the Partnership in Priority Areas Program—PNII, under MEN-UEFISCDI.
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Craiu, A., Craiu, M., Diaconescu, M. et al. 2013 Seismic swarm recorded in Galati area, Romania: focal mechanism solutions. Acta Geod Geophys 52, 53–67 (2017). https://doi.org/10.1007/s40328-016-0161-9
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DOI: https://doi.org/10.1007/s40328-016-0161-9