• Journal of the Korean Geophysical Society
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• v.7 no.3
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• pp.185-192
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• 2004

We calculate moment magnitudes of earthquakes occurred in the southern part of the Korean Peninsula from January, 2001 to February, 2004 and compare them with local magnitudes published by KMA(Korea Meteorological Administration) and KIGAM(Korea Institute of Geoscience and Mineral Resources). From this study, we find that local magnitudes of KIGAM have higher correlation with moment magnitudes than local magnitudes of KMA have. We induce a proper conversion formula by analyzing relation between published local magnitudes and calculated moment magnitudes. The induced formula can be used to unify kinds of magnitudes in earthquake catalogues and unified earthquake catalogues can be applied as necessary factors for analyzing earthquake characteristics, seismic hazards or attenuation formulas in the southern part of the Korean Peninsula.

• Journal of the Korean Geophysical Society
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• v.4 no.1
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• pp.47-55
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• 2001

conversion equations to calculate seismic moment(M_0) from body-wave magnitude(m_b), surface-wave magnitude(M_s), or both were derived by using 50 earthquakes occurred within 32～44°N and 123～133°E whose M_0 were determined together with m_b or M_s. We divided those earthquakes into the deeper and the shallower ones based on the reference focal depth of 70 km. The unit of M_0 is dyne-cm. In case of M_s, the deeper earthquakes exhibit the higher seismic moment than the shallower ones. Standard deviations associated with conversion equations for deeper and shallower earthquakes are 0.25 and 0.16, respectively, in moment magnitude. , for deeper earthquakes , for shallower earthquakes. In case of m_b, the dependence of conversion equation on focal depth is not clearly observed. Associated standard deviation is 0.28 in moment magnitude. In case that both m_b and M_s were determined, a new magnitude, , were defined for shallower earthquakes to derive a more stable conversion equation. Associated standard deviation is 0.14 in moment magnitude. Conversion equations above can be used to unify the earthquake size into a single magnitude type, i.e., moment magnitude, in and around the Korea Peninsula.