Abstract
Positions of earthquakes over 5th magnitude were investigate in Taiwan
region and adjacent Philippine Sea Plate. Purpose of this paper was to
establish earthquakes tidal periods in range of Moon sidereal rotation
cycle. Because sidereal Moon cycle reflects variation in length of day
of Earth, positions of earthquakes on this graph stated positions on
Moon’s orbit and from it followed the tidal frequences knowing time. 849
earthquakes after declusterization were investigated in three time
periods
1962-1982, 1983-2002 and 2003-2024. Histograms of earthquakes compiled
for
Moon crossing equator from south, reaching maximum Moon declination,
reaching Moon equator from north and reaching maximum negative
declination, presented tidal frequence 6.83 days, 13.66 days and their
multiples. By this way stated earthquake occurrence periods are only
31.8 %, but remaining earthquakes have also tidal origin given tectonic
position on Taiwan and cumulative action of northsouth and westward
directing forces.