Can the position of the moon or planets affect seismicity?
The question often arises as to whether astronomical events, such as planetary alignments, can significantly influence the occurrence of earthquakes. The moon, sun, and other planetary bodies in our solar system influence the earth in the form of perturbations to the gravitational field. The relative amount of influence is proportional to the objects mass and inversely proportional to the cube of its distance from the earth. * The general idea is that strains in the earths crust caused by perturbations in the gravitational field may influence when an impending earthquake will occur (like the straw that broke the camel’s back). If this were indeed the case, we would expect to see a correlation between rate at which earthquakes occur and the perturbations to the gravitational field. The dominant perturbation in the earths gravitational field generates the semi-diurnal (12 hour) ocean and solid earth tides which are primarily caused by the moon (due to its proximity) and the sun (due to i
