Abstract: The features of larger earthquakes before 15 subsequent strong earthquakes are stud 1ed in this paper from the nonlinear viewpoint. Two useful indexes to judge the subsequent strong earthquakes are discovered. The two indexes are: 1. The included angle Aτbetween local mean lunar times of two larger earthquakes before the subsequent strong shock will be smaller than 45°; 2. The magnitude of the late larger earthquake is higher than the former one.

Key words: Nonlinearity, Solid tide, Earthquake prediction, Subsequent strong earthquake