A unified moment magnitude earthquake catalog for Northeast India
Ranjit Das, Claudio Meneses Villegas
Abstract
Earthquake-related studies on seismicity and seismic hazard assessment need a homogenous earthquake catalog for the region studied. A homogenous earthquake catalog for Northeast India region was compiled using derived regional and global empirical relationships between different magnitudes and moment magnitude based on an improved error-corrected methodology suggested in the recent literature. To convert smaller magnitude earthquakes, global empirical equations were derived and used. A procedure is suggested to change different magnitudes into moment magnitude. A homogenous earthquake catalog of 9845 events was compiled for the time period 1897–2012. Entire magnitude range (EMR) was found to be the most reasonable method for estimating magnitude of completeness. Derived local and global empirical equations are useful for every seismic hazard or seismicity study. A complete and consistent homogenized earthquake catalog prepared in this study could provide good data for studying earthquake distribution in Northeast India. By carefully converting these original magnitudes into homogenized Mw magnitudes, an obstacle is removed for the consistent assessment of seismic hazards in Northeast India.