NEPAL EARTHQUAKE

Aditya Kumar Anand

Project Assistant Level – 2

CSIR-Central Road Research Institute

EarthquakesAn earthquake is the shaking and vibration on the surface of the earth resulting

from underground movement along plate margins. When plates move past, towards or away from each other the movement is not

smooth. Friction causes the plates to get stuck. This causes pressure to build up. Earthquakes occur when this build up of

pressure is released. The point where the earthquake starts is called the focus. This pressure travels up to the Earth's crust and escapes at the epicentre of the

earthquake.In an earthquake, energy is released in the form of waves. These are called seismic

waves. The waves spread out from the focus

The strongest waves are found near the centre of the earthquake. This means that the most severe damage caused by an earthquake will happen close to the epicentre.

The diagram above illustrates how the movement of two plates at the plate boundary creates pressure deep inside the Earth.

Measurements of Earthquakes• The power of an earthquake is

measured using a seismometer.

• A seismometer is a sensitive machine, which picks up the vibrations caused by the earthquake. It plots these vibrations on a seismograph.

• The strength or magnitude of an earthquake is measured using a scale called the Richter Scale.

• The Richter Scale is numbered 0-10.

Social Impacts Economic Impacts Environmental Impacts

Short term impacts People may be killed or injured. Shops and business are destroyed. The built landscape is destroyed.

Homes may be destroyed. Looting may take place.Fires spread due to gas pipe explosions. Fires can damage areas of woodland.

Essential services may be disrupted for exampletransport and communication links

Transport and communication systems are disrupted. Landslides may occur.

Water pipes may burst and water supplies may be contaminated

Trade not be carried out easily due to the poor transport and communication systems therefore a loss of money.

Tsunamis may cause flooding in coastal areas.

Long Term Impacts Disease may spread. The cost of rebuilding a settlement is high. Important natural and human

landmarks may be lost.

People may have to be re-housed, sometimes in refugee camps.

Investment in the area is focused only on repairing the damage caused by the earthquake. Income is lost.

Old buildings in some cases will not be able to be restored however new developments.

Nepal Earthquake

Date 25 April 2015

Origin time 11:56:26 NSTMagnitude 7.9Mw

Depth 15.0 kilometres (9 mi)Epicentre 28.147°N 84.708°EType Thrust Areas affected Nepal

IndiaChinaBangladeshBhutan

Max. intensity IX (Violent)Casualties above 10000 dead and 11,786

injured

Geological factors for Nepal Earthquake • Nepal lies towards the southern limit of the diffuse collisional boundary where

the Indian Plate under thrusts the Eurasian Plate. occupying the central sector of the Himalayan arc nearly one-third of the 2,400 km (1,500 mi) long Himalayas.

• The convergence rate between the plates in central Nepal is about 45 mm (1.8 in) per year.

• The location, magnitude, and focal mechanism of the earthquake suggest that it was caused by a slip along the Main Frontal Thrust.

• Based on a study published in 2014 of the Main Frontal Thrust on average a great earthquake occurs every 750 ± 140 and 870 ± 350 years in the east Nepal region.

• A study from 2015 found a 700-year delay between earthquakes in the region. • The study also suggests that because of tectonic stress build up the earthquake

from 1934 in Nepal and the 2015 quake are connected following a historic earthquake pattern (Not verified)

Nepal is disaster prone country due to Various factors

• Rugged & fragile geomorphic condition• Variable climate conditions• Increasing population• Poor economic conditions• Unplanned settlements

Seismic Zone Map Of India