Full and new moons seem to make earthquakes more likely – at least the largest, most devastating quakes.
Although the effect is too small to make much difference in preparing for earthquakes in the short term, the discovery could some day provide key insights into the ways that they develop and grow.
During full and new moons, the sun, moon and Earth align, meaning that gravity tugs more strongly on the planet’s crustal plates. The resulting “Earth tides” and increased tidal movements in the oceans can add to the stresses on earthquake faults.
It therefore seems plausible that they might make the faults more likely to slip. A few studies have previously found hints that this might be true, but the effect of the tides has barely been detectable.
