NEPAL Earthquake

An earthquake with an intensity of 7.9 on ritcher scale with epicenter 77 kilometer north-west of Kathmandu has been experienced in some parts of India.

  • The impact of the earthquake has been felt in almost all northern States in India particularly in Bihar, Uttar Pradesh, Sikkim, West Bengal.

NEPAL EARTH QUAKEDetails:

  • The Earthquake has occurred at a depth of 10 Km with its Epicentral Region located in Nepal about 80 Km NW of Kathmandu.
  • More than 30 aftershocks have also been reported.
  • In geological terms, the tremor occurred like clockwork, 81 years after the region’s last earthquake of such a magnitude, in 1934.

Specific cause of the Earth Quake:

  • It was triggered by the India tectonic plate, which is moving northwards into central Asia.
  • This results in thrust-faulting and has thrown up the Himalayan mountain range.
  • The India tectonic plate moving north at about 45mm a year is pushing under the Eurasian plate beneath the  Himalayas.
  • Two tectonic plates meet beneath the Himalayas along a fault line.

  • It has triggered several other significant earthquakes in this region, including the
    • 1934 quake at Bihar, which reached a magnitude of 8.2;
    • 1905 event at Kangra in a magnitude 7.9;
    • 2005 Kashmir earthquake, which reached 7.6.
  • The Indian subcontinent collided with the Eurasia plate about 40 million to 50 million years ago.

Effects of the Earthquake:

  • As the plates push against each other, friction generates stress and energy that builds until the crust ruptures.

Why Nepal?

Nepal is prone to destructive earthquakes, not only because of the massive forces involved in the tectonic collision, but also because of the type of fault line the country sits on.

  • Normal faults create space when the ground cracks and separates.
  • Nepal lies on a so-called thrust fault, where one tectonic plate forces itself on top of another.
  • The most visible result of this is the Himalayan mountain range.
  • The fault runs along the 1,400-mile range, and the constant collision of the India and
  • Eurasia plates pushes up the height of the peaks by about a centimeter each year.

Terminology:

  • Earthquakes

are the manifestations of sudden release of strain energy accumulated in the rocks over extensive periods of time in the upper part of the Earth.

  • Aftershock:

An earthquake that follows a large magnitude earthquake called, ‘main shock’ and originates in or around the rupture zone of the main shock. Generally, major earthquakes are followed by a number of aftershocks, which show a decreasing trend in magnitude and frequency with time.

  • Fault:

A weak plane in the Earth’s crust and upper mantle along which two blocks of rock mass rupture or slip past each other. Faults are caused by earthquakes and earthquakes are likely to reoccur on pre-existing faults, where stresses are accumulated.

  • Epicentre:

It is the point on the surface of the earth, vertically above the place of origin (hypocentre) of an earthquake. This point is expressed by its geographical Coordinates in terms of latitude and longitude.

Sources: PIB, ET, Google, IMD.

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