ORIGINAL ARTICLE Discrimination of earthquakes and quarry blasts in the eastern Black Sea region of Turkey Şeyda Yılmaz & Yusuf Bayrak & Hakan Çınar Received: 15 December 2011 / Accepted: 12 November 2012 / Published online: 30 November 2012 # Springer Science+Business Media Dordrecht 2012 Abstract In recent years, a large number of quarry blasts have been detonated in the eastern Black Sea region. When these blasts are recorded by seismic sta- tions, they contaminate the regional earthquake catalog. It is necessary to discriminate quarry blast records from the earthquake catalogs in order to determine the real seismicity of the region. Earthquakes and quarry blasts can be separated through different methods. These methods should be applied concurrently in order to safely distinguish these events. In this study, we dis- criminated quarry blasts from earthquakes in the eastern Black Sea region of Turkey. We used 186 seismic events recorded by the Karadeniz Technical University and Bogaziçi University Kandilli Observatory Earthquake Research Institute stations which are Trabzon, Espiye, Pazar, Borçka, Aydıntepe, and Gümüşhane between years of 2002 and 2010. For the discrimination of quarry blasts from earthquakes, we used both, statistical meth- ods (calculation of the maximum ratio of S to P waves (S/P), complexity (C)) and spectral methods (spectro- gram calculation). These methods included measuring the maximum amplitude S/P, C, spectral ratio, and time- frequency analysis. We especially relied on two- dimensional time-frequency analysis methods to dis- criminate quarry blasts from earthquakes in Turkey. As a result of this study, 68 % of the examined seismic events were determined to be quarry blasts and 32 % to be earthquakes. The earthquakes occurring on land are related to small faults and the blasts are concentrated in large quarries. Nearly 40 % of the earthquakes occurred in the Black Sea, most of them are related to the Black Sea thrust belt, where the largest earthquake was ob- served in the time period studied. The areas with the largest earthquake potential in the eastern Black Sea region are in the sea. Keywords The eastern Black Sea . Earthquakes . Quarry blasts . Time-frequency analysis 1 Introduction The eastern Black Sea region is related to the Eastern Pontides, known as the eastern Black Sea mountain belt. This belt takes part of the Alpine Himalayan orogen and elongates for about 600 km from Samsun in the W to Hopa in the E. The N-S extension from Trabzon (N) to Erzincan (S) amounts to approximately 125 km. Active deformation zones in the eastern Pontides create three different seismic belts from south to north (Bektaş et al. 1995; Eyüboğlu et al. 2007). These belts represent (1) a southern seismic zone J Seismol (2013) 17:721–734 DOI 10.1007/s10950-012-9348-x Ş.Yılmaz : Y. Bayrak (*) : H. Çınar Department of Geophysics, Karadeniz Technical University, Trabzon, Turkey e-mail: bayrak@ktu.edu.tr Ş.Yılmaz e-mail: seydayilmaz@ktu.edu.tr H. Çınar e-mail: cinar@ktu.edu.tr