Relationships among magnitudes and seismic moment of earthquakes in the Taiwan region

Abstract

The seismic moments (Mo), body-wave magnitudes (mb), and surface-wave magnitudes (Ms) of 201 Taiwan earthquakes with 4.8 ≤ mb ≤ 6.6 published in the Global CMT catalog from 1976 to 2006 are used to study the correlations among the three source parameters. The resultant relationships are: log(Mo) = (1.07 ± 0.04) Ms + (18.72 ± 0.20); log(Mo) = (1.73 ± 0-09) mb + (15.09 ± 0.52); and Ms = (1.46 ± 0.08) mb - (2.52 ± 0.43). The three relationships have high agreement with those of earthquakes in the circum-Pacific seismic belt. This might imply that the tectonic conditions and source properties of the Taiwan region behave like the average ones of the circum-Pacific seismic belt. The relationships between the three source parameters and local magnitude are: log(Mo) = (1.27 ± 0.06) ML + (17.23 ± 0.35); mb = (0.66 ± 0.03) ML + (1.69 ± 0.17); and Ms = (1.03 ± 0.06) ML - (0.53 ± 0.36).