Statistical analysis of earthquake catalogs for seismic hazard studies around the Karliova Triple Junction (eastern Turkey)

A complete and comprehensive earthquake catalog is a substantial input to do probabilistic seismic hazard analysis. The Karliova triple junction (eastern Turkey) is characterized by an active seismicity mostly in the shallow crust. Origin times, earthquake locations, and magnitudes reported by the Kandilli Observatory and Earthquake Research Institute, Boğaziçi University (KOERI) and three international agencies (ISC, IRIS and EMSC) in the region bounded by latitudes 37.5° and 40.5° N and longitudes 37.5° and 42.5° E have been gathered in order to quantify the seismicity around the study area and calculate associated seismic parameters. The Magnitudes of completeness (Mc) and Gutenberg-Richter (GR) recurrence parameters (a- and b-values) have been estimated. The same Mc value of 2.7 has been obtained for all catalogs. After 2014, all earthquakes with magnitudes higher than 2.0 are reliably recorded. However, the b-value varied from 0.97 to 1.28. High b-value anomalies mostly for earthquakes with shallow depths (5–15 km) have been observed. A relatively lower b-values are found at depths