NO MATTER where they hit, large earthquakes can trigger a multitude of tiny tremors right across the globe.
Geologists have long suspected that this was the case, the culprit being waves that travel along the Earth鈥檚 surface, including Love waves and Rayleigh waves.
Now Aaron Velasco of the University of Texas at El Paso and colleagues have found that large earthquakes cause many more tiny tremors than previously thought. The team gathered data on 15 earthquakes of magnitude 7 or greater from more than 500 seismographic stations worldwide.
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In the 5 hours before the waves from a distant earthquake passed through these regions, the mean number of quakes detected globally was around 600. In the 48 minutes after the passage of Love waves, the average rate of these tremors rose by 37 per cent; for Rayleigh waves, the jump was 60 per cent (Nature Geoscience, ).
Roger Musson of the British Geological Survey says, 鈥淚t means that this remote triggering is much more common than anyone supposed.鈥�
