The research suggests that both magnitude and frequency of earthquakes are related to plate collision speed.
Earthquakes that happen in densely populated mountainous regions, such as the Himalaya, spell bigger earthquakes because of a fast tectonic-plate collision, according to a new study reported at Phys.org.
Researchers from Geophysical Fluid Dynamics – ETH Zürich in Switzerland, say their findings give people a more complete view of the risk of earthquakes in mountainous regions.
The new study shows that the frequency and magnitude of large earthquakes in the densely populated regions close to mountain chains – such as the Alps, Apennines, Himalaya and Zagros – depend on the collision rate of the smaller tectonic plates.
In 2015, a magnitude 7.8 earthquake struck Gorkha-Nepal, and a year later, Norcia, Italy suffered a magnitude 6.2 earthquake. Previous research has attempted to explain the physical causes of earthquakes like these, but with ambiguous results. For the first time, the new study shows that the rate at which tectonic plates collide controls the magnitude of earthquakes in mountainous regions.
“The impact of large earthquakes in mountain belts is devastating,” commented Luca Dal Zilio, lead author of the study from Geophysical Fluid Dynamics – ETH Zürich.
“Understanding the physical parameters behind the frequency and magnitude of earthquakes is important to improve the seismic hazard assessment. By combining classical earthquake statistics and newly developed numerical models, our contribution addresses a crucial aspect of the seismic hazard, providing an intuitive physical explanation for a global-scale problem. Our scientific contribution can help the society to develop a more complete view of earthquake hazard in one of the most densely populated seismic zones of the world and ultimately take action accordingly.”
There are seven large tectonic plates and several smaller ones in the earth’s lithosphere – its outermost layers. These plates move, sliding and colliding, and that movement causes mountains and volcanoes to form, and earthquakes to happen.
via Tallbloke’s Talkshop
December 5, 2017 at 03:39AM