Expanding Moment Magnitude Pools for Earthquake Magnitude Homogenization

Abstract

A comparison on the influence of different moment magnitude pools on magnitude homogenization regressions was presented. The control moment magnitude pool is composed of earthquake records from GCMT. One version of expanding this base is to add earthquakes with a moment magnitude recorded by seismological agencies related to GCMT. Another approach to expanding the base is to add earthquakes from seismological agencies and projects that show a significant statistical correlation to GCMT via hypothesis testing. These moment magnitude pools were developed for Indonesia and South Korea. Magnitude homogenization was conducted by performing linear least squares regressions between the three moment magnitude pools and commonly used magnitude types from international seismological agencies ISC and NEIC. Magnitude homogenization regressions were also conducted on local Indonesian and South Korean agencies, DJA and KMA, respectively, with their various magnitude types. Most of the moment magnitude pools involving DJA and virtually all South Korean-related agencies ended up being identical, primarily due to the local magnitude types available for DJA, and the low number of earthquakes recorded for South Korea. A majority of the regression parameters for Indonesia and South Korea were statistically similar for surface and body wave magnitude types.