London, November 05: Some of the most violent earthquakes that have occurred unexpectedly in places with no recent record of tremors may be the aftershocks of previous earthquakes that took place decades or even centuries ago, scientists have discovered.
Earthquakes usually occur at the boundary of two or more tectonic plates – the massive chunks of the earth’s crust that grind slowly against one another. However, they can also occur many hundreds of miles from a fault line and it is these earthquakes that scientists believe may be the result of long aftershocks rather than background seismic activity.
A laboratory study that tested how tectonic faults work has found that the further away an earthquake is from such fault line, the stronger the likelihood that it could be the long aftershock of a previous earthquake that has taken many years to make itself felt in terms of a second series of violent ground movements.
–Agencies