The effect of earth tides in triggering earthquake as clearly observed in some specific regions of Japan

The question of whether earth tides trigger earthquakes has been the subject of debate for years. Recent studies, at last, have proven the significance of the earth tide effect in triggering earthquakes, and they further reported that the direction of the compressional stress at a region created by the earth tide almost coincides with that of the dominant principal pressure axes of the focal mechanisms at the region. This suggests that there might be specific positions of the Moon, Sun and Earth, known as lunar phases that create effective tidal force for earthquakes at each fault. So that, this paper examines the relationship between earthquakes and the lunar phases in some specific regions of Japan, and the significant effect of earth tide in triggering earthquakes is confirmed.