The Calculation of Local Magnitude from the simulated Wood-Anderson Seismograms of the Short-Period Seismograms in the Taiwan Area

The attenuation function, logA0(�.),used in the calculation of local magnitude is derived for the Ta iwan area.The simulated Wood-Anderson seismograms are con structed by using digital three-components short-period seismogram of the Central Weather Bureau Seismic Network, (CWBSN).The decay of peak amplitude with dis tance is the attenuation characteristic of seismic energy.Also, it essentially represents the distance correction term, log Ao (A), after a proper normalization.Considering the focal depth of earthquakes in the Taiwan area, the logA0(6.)functions are: