It is a basic fact that earthquake occurrence can be modulated and triggered by the syzygial tide.

望潮触发和调制地震的发生已是一个基本事实。

The syzygial tide is that the maximum amplitude period of semi-monthly tide added to the semi-diurnal and full-diurnal tides.

望潮即是半月潮幅度最大时段再迭半日潮和全日潮。