Dear reader we have discussed many posts about tectonic causes of earthquake. Recently a magnitude 7.8 earthquake hit Nepal on April 25, 2015. The region where earthquake generated is very crucial location where large earthquakes are supposed to be occurred.
We have learnt that the great Mount Everest was once under ocean which was a erupted due to release of huge strain energy at plate boundary. We know earthquakes are likely to occur at major plate boundary. But the thrusts generating in Himalayan region seldom produce major earthquakes.
The significant earthquakes we can recall from history are in 1988 and 1934.
1988-magnitude 6.9 earthquake resulted fatalities of 1500 having epicenter 240 Km from present earthquake in Nepal.
1934-magnitude 8.0 earthquake caused fatalities of 10,600 which is known as Nepal-Bihar earthquake and the epicenter was almost in identical location of that event of 1988.
Now come to the point- why this earthquake occurred?
The thrust faulting of subduction zone between India plate and Eurasia plate-The Eurasia plate is overriding past India plate and the direction is toward North. The thrust faulting is found near or on the main thrust in this region.
Continental collision of Eurasia and India plate produce seismic activity in this region. The converging rate (relative) is (40-50) mm per year in NNE (North-NorthEast) direction and mountain range of Himalayan range gradually uplifting.
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