A STUDY ON THE CHARACTERISTICS OF GUMUSHANE SEISMICITY: ANALYSES OF REGION-TIME PARAMETERS

Abstract

The proposed study is focused on the identification of region-time characteristics of earthquakes in Gumushane, Turkey. Detailed statistical evaluations were achieved by considering the most frequently used size-scaling parameters such as seismotectonic b-value, fractal dimension Dc-value, standard normal deviate Z-value and recurrence time of earthquakes. Used earthquake catalog is homogeneous for duration magnitude, M-d, and consists of 2902 shallow earthquakes with 1.0 <= M-d <= 6.5 in about 47.76-years period between 1970 and middle of 2018. b-value is computed as 1.02 +/- 0.02 with a completeness level of 2.8, and this result indicates that frequency-magnitude distribution of seismicity in Gumushane is well represented with a b-value typically close to 1.0. Dc-value is calculated as 1.57 +/- 0.03 with a scale invariance between 4.96 and 86.28 km. This Dc-value means that seismic activity is more clustered in smaller areas or at larger scales in Gumushane. The analysis on the recurrence times of earthquakes implies that Gumushane has not a significant earthquake potential for the great earthquakes. Regional variation of b-value shows that small b-values were observed in and around Kelkit and Kose, and these regions may have a possible earthquake hazard and risk in the future. Z-value analysis suggests that there are not noticeable seismicity rate changes in the mid-2018. These statistical results indicate that the seismic hazard is low and seismic risk is minor in the intermediate term in Gumushane.