Tidal Forces Can Trigger or Slow Earthquakes

The pull of the moon and the sun that causes Earth’s tides can also trigger earthquakes, according to an analysis of 2,000 quakes by scientists at UCLA and in Japan. The largest tides are linked to an increased number of earthquakes on shallow thrust faults, said Elizabeth Cochran, a UCLA graduate student and lead author of the report in the current issue of the journal Science. The authors suspect tidal forces speed up or slow down the timing of earthquakes on faults that are about to rupture because of other stresses.