In a study, researchers have unveiled the mechanism behind strange earthquakes that occur away from tectonic plate boundaries. Normal earthquakes are generated along the tectonic plates due to movements of these plates. However, researchers have revealed that strange earthquakes that occur away from fault lines are generated by a motion of particles beneath the plates.
As per the reports, interplate earthquake accounts for mere 2 percent of the total earthquakes that occur all over the globe and can reach up to magnitude 7 on Richter scale. Although it may look a small number but ignoring it can be a blunder causing loss of life and property.
While explaining the occurrence of strange earthquakes researcher said that very hot, molten, semi-liquid rock constantly flows beneath the Earth’s crust due to which top layer of Earth gets heated up and then cools down. Heating expands the top surface while cooling again contracts it. The whole process repeats itself, generating movement in plates at the surface which is driving intraplate seismicity and determining in large part where those earthquakes occur.
[blockquote]”This will not be the last word on the origin of strange earthquakes. However, our work shows how imaging advances in seismology can be combined with mantle flow modelling to probe the links between seismicity and mantle convection,” said Thorsten Becker, lead author of the study and professor of Earth sciences at the University of Southern California (USC) Dornsife College of Letters, Arts and Sciences. [/blockquote]
For the study, Becker constructed an updated version of mantle flow model and studied motion of plates beneath the mountain belt in the Western US. Researchers chose the area as it is seismically active and sits on top of volcanic hotspot.
Scientists found that small-scale convective current flowing beneath the surface caused earthquakes. While previous studies said that earthquakes occur away from fault line due to variable density of tectonic plates.
Study authors found that convective currents correlated with seismic event while variables density of tectonic plates showed very poor correlation with the seismic events.
The study will help in better predicting occurrence of strange earthquakes that are generated away from tectonic plates.
The study appeared in the journal Nature.
First published on Monday, August 31, 2015, 06:36 AM