Main Article Content
The relation between earthquake and planet motion is one of topics interesting to people. Based on conservation law of energy, this paper proves that the energy release by earthquake proportions to the square of velocity of Earth’s rotation, while velocities of revolution of Earth and Moon remain unchanged. Furthermore, earthquake happening in pulse-mode is proved by Principle of minimum energy release. Testing examples of Japan 2011-3-11 earthquake, 1960 Great Chilean earthquake, and 2004 Indonesia Sumatra earthquake show that the shortening of a day caused by earthquake depends on the time of earthquake lasting, the shortening, the lasting.