Abstract: | The data of short-period seismograms had been collected widely in the mainland area of China not including Xinjiang and Tibet.
The physical quantities of Lg wave are determined respectively in the five subregions. The group velocities of priminary arrival
and maximum amplitude of Lg wave are equal to 3.54±0.02 km/s and 3.30±0.05 km/s, respectively. The periods of Lg waves are
between 0.2s to 1.2s, averaging 0.7s. The γ-values of Lg waves in the five subregions are equal to 0.0034±0.0001 km−1 for East, 0.0031±0.0004 km−1 for Southwest, 0.0027±0.0004 km−1 for Northeast, 0.0022±0.0001 km−1 for South, and 0.0021±0.0002 km−1 for Northwest subreqion, respectively. The average γ-value for the five subregions, γ=0.0027±0.0006 km−1. The relations among the amplitude ratioH/Z, the station correctionD
z andD
h of amplitudes, and among them and station site condition are discussed.
The subregional magnitude calibration functions ofm
Lg had been established according to each regional γ-value. From these, the unified magnitude calibration function of Chinese
mainland not including Xinjiang and Tibet was given by
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