They found that the same applies to solar tides, which are not as strong as lunar tides. These findings support the view that earthquakes begin gradually days in advance. The relation is very weak, at best.
Earthquakes follow their own schedule.
Vidale reports on more than 13,000 earthquakes over 25 years, from 1969 to 1994, along the San Andreas fault near Parkfield and the Calaveras fault in Northern California. He studied when the earthquakes struck and calculated the stresses on the faults at the times they occurred, and at random times. The findings are reported in the October issue of the Journal of Geophysical Research, the premier scholarly journal in solid earth geophysics. This small correlation is statistically insignificant, he said. Even if this preparatory phase could be identified in advance, it would not necessarily indicate whether the approaching earthquake will be small, moderate or strong, he cautioned.