High tides appear to push strained faults over the edge, triggering massive earthquakes, according to a new study .
Seismologists at the University of Tokyo discovered a link between the occurrence of large earthquakes and the height of high tides. The added stress increases the probability of small movements cascading into much larger tremor. The information could help researchers predict when large quakes are more likely to occur.
BBC News describes the study:
The team reconstructed the size of tidal stresses – rather than just looking at the timing of tidal phases – in the two weeks prior to large quakes (of Magnitude 5.5 or greater).
There was no clear correlation found between tidal stress and small earthquakes. But they found that the fraction of large earthquakes increases in line with the size of tidal stress.
The Japanese team found that some of the largest and most devastating earthquakes in recent years—the magnitude 9.0 Tohoku temblor in 2011 that led to the Fukushima Daiichi nuclear plant meltdown, the magnitude 8.8 Chilean quake in 2010, and the 2004 Sumatran event—were all correlated with times of high tidal stress.