Investigating the consistency of online earthquake catalogs of Turkey and surroundings

There are several national and international online earthquake catalogs publishing the focal parameters of earthquakes in Turkey and surroundings. While international seismological centers provide global earthquake catalogs with data from around the world, as well as their own solutions, local and regional seismic centers are confined to publish regional catalogs with solutions derived exclusively from their own data. In this study, we investigate the consistency of the focal parameters provided by national and international agencies for a large number of earthquakes which occurred in and around Turkey during the period 2000–2017. Agencies that analyze earthquakes in this region on a regular basis and whose data are used in this study are the Bogazici University–Kandilli Observatory and Earthquake Research Institution (BOUN–KOERI; “KOERI” from now on) and the Disaster and Emergency Management Authority, Earthquake Research Directorate (AFAD–ERD; “AFAD” from now on) as well as one of the leading international seismological agencies, the International Seismological Centre (ISC). The study area covers the region bounded by the coordinates 35–42° N and 26–45° E. Estimations of origin times, epicentral coordinates, focal depths, and magnitudes, as well as their uncertainties, provided by AFAD, KOERI, and ISC, are examined. The magnitude values of these three centers are homogenized and checked against each other. Furthermore, the completeness (with regard to magnitude) of each of the tested catalogs is defined, as well as its variation in space and with time. Finally, it is shown that the locations provided by KOERI and AFAD are similar to each other, while ISC solutions are closer to those of KOERI.