Why Himalayas are hit by bigger earthquakes found

      GENEVA :    Earthquakes hitting densely populated mountainous regions, such as the Himalaya, are bigger in magnitude because of a fast tectonic-plate collision, according to a study. The 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.

       The finding by researchers from ETH Zurich in Switzerland Provides a more complete view of the risk of earthquakes in mountainous regions. 

      In 2015, a magnitude 7.8 earhquake 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 earthquake like these, but with ambiguous results.


 For the first time, researchers show that the rate at which tectonic plates collide controls the magnitude of earthquake in mountainous regions. This because the faster they collide, the cooler the temperatures and the larger the relative number of large earhquakes, they said 

    "The impact of large earthquakes in mountain belts is devastating". said Luca Dal Zilio from ETH Zurich. and she also said "Under standing the physical parameters behind the frequency and magnitude of earthquakes is important to improve the seismic hazard assessment". said Zilio, lead author of the study published in the journal Earth and Planetary Science Letters.

     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 volcanoes to form, and earthquakes to happen.

    The researchers developed 2D models that simulate the way the tectonic plates move and collide. The seismo-thermo mechanical(STM) modelling approach utilises long- time sacle processes to explain short time scale problems, replicating the result observed from the historical earthquake catalogues. it shows graphically the distribution of earthquakes by their movement in the orogeny -a formation of mountains..