Strong Earth Tides Can Trigger Earthquakes

[zavvy]

<b>Strong Earth Tides Can Trigger Earthquakes</b><br /><br />LINK<br /><br />Earthquakes can be triggered by the Earth's tides, UCLA scientists confirmed Oct. 21 in Science Express, the online journal of Science. Earth tides are produced by the gravitational pull of the moon and the sun on the Earth, causing the ocean's waters to slosh, which in turn raise and lower stress on faults roughly twice a day. Scientists have wondered about the effects of Earth tides for more than 100 years. (The research will be published in the print version of Science in November.) <br /><br />"Large tides have a significant effect in triggering earthquakes," said Elizabeth Cochran, a UCLA graduate student in Earth and space sciences and lead author of the Science paper. "The earthquakes would have happened anyway, but they can be pushed sooner or later by the stress fluctuations of the tides." <br /><br />"Scientists have long suspected the tides played a role, but no one has been able to prove that for earthquakes worldwide until now," said John Vidale, UCLA professor of Earth and space sciences, interim director of UCLA's Institute of Geophysics and Planetary Physics, and co-author of the paper. "Earthquakes have shown such clear correlations in only a few special settings, such as just below the sea-floor or near volcanoes." <br /><br />"There are many mysteries about how earthquakes occur, and this clears up one of them," Vidale said. "We find that it takes about the force arising from changing the sea level by a couple of meters of water to noticeably affect the rate of earthquakes. This is a concrete step in understanding what it takes to set off an earthquake." <br /><br />Cochran, Vidale and co-author Sachiko Tanaka are the first researchers to factor in both the phase of the tides and the size of the tides, and are using calculations of the effects of the tides more accurate than were available j

 

[nexium]

It follows logically that earthquakes are triggered minutely by tides. Even though the researchers claim high confidence, I suspect the effect is close to infinitesmal. Neil