Regression Relations for Conversion of Various Magnitude Types and Catalogs for the Earthquakes of Turkey and Vicinity

Abstract

Online Material: Table of regression parameters. Homogeneous earthquake catalogs are needed for various seismological studies, such as hazard analysis and seismicity. In most of the research in question, it is preferred to use moment magnitude M w. Turkey is a seismically active region due to the complex tectonic structure. This high seismicity requires studies on earthquakes that in turn must rely on a uniform catalog, that is, the catalog must be based on a single‐magnitude type. Several national and international organizations record and evaluate the earthquake data to calculate and catalog the magnitude values in various types. This study was carried out to introduce the regression relations between these magnitude scales to provide uniform catalogs for Turkey. A number of studies have been implemented to estimate the relationship between various magnitude scales for global and regional datasets. Although the moment magnitude is the most reliable magnitude scale (Kagan, 2002b, 2003; Castellaro et al. , 2006), it is the most rare. In the regional earthquake catalog of Turkey, compiled by Bogazici University Kandilli Observatory and Earthquake Research Institute–National Earthquake Monitoring Centre (B.U.KOERI–NEMC), there are 2110 body‐wave magnitudes, 1958 local magnitudes, 1511 duration magnitudes, 405 moment magnitudes, and 254 surface‐wave magnitude values published (all magnitudes equal or greater than 4.0) for 4074 events within the period from 1900 to 2014. Similarly, there is a shortage of moment magnitude data in the catalogs of the International Seismological Centre (ISC). A search of the ISC bulletin for events in Turkey with magnitude equal or greater than 4.0 yielded 4246 body‐wave magnitude and 636 surface‐wave magnitude values. There are only 151 moment magnitude reported in the Global Instrumental Earthquake Catalogue released by the ISC and Global Earthquake Model (GEM) effort. With the same search parameters, there are 219 earthquakes with moment magnitude values …