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NEPAL
EARTHQUAKE
Aditya Kumar Anand
Project Assistant Level – 2
CSIR-Central Road Research Institute
Earthquakes
An 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 diagram above illustrates how the movement of two plates
at the plate boundary creates pressure deep inside the Earth.
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.
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
Short term impacts
Long Term Impacts
People may be killed or injured.
Economic Impacts
Environmental Impacts
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
Tsunamis may cause flooding in
communication systems therefore a coastal areas.
loss of money.
Disease may spread.
The cost of rebuilding a settlement
Important natural and human
is high.
landmarks may be lost.
People may have to be re-housed,
sometimes in refugee camps.
Investment in the area is focused
Old buildings in some cases will not
only on repairing the damage
be able to be restored however
caused by the earthquake. Income
new developments.
is lost.
Nepal Earthquake
Date
25 April 2015
Origin time
11:56:26 NST
Magnitude
7.9Mw
Depth
15.0 kilometres (9 mi)
Epicentre
28.147°N 84.708°E
Type
Thrust
Areas affected
Nepal
India
China
Bangladesh
Bhutan
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