Name: Joshin Rexy
Submitted to: Nesthangam
Earthquake
Hope it helped.
Project done on Earthquake.
Preface
I, Joshin, aged 15 has been writing about
earthquakes, till the class of 9. I hope it will
help to those who are reading my project. This
small project is about earthquake and its
details. The sources that influenced me about
this topic is my own project that even I took for
earthquake. In the following project is about
introduction to earthquake, causes of
earthquake, effects of earthquake, a case
study, conclusion and bibliography. At the end,
I thank my book also (earthquake and its
effects) who helped me to get to this point,
Yours sincerely,
Joshin
Content
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Introduction
Causes of earthquake
Effects of earthquake
Case study
Conclusion
Bibliography
Introduction
Earthquakes are one of the most destructive among the natural
disasters. It occurs due to sudden transient motion of the
ground as a result of release of elastic energy in a matter of few
seconds. The impact of the event is most traumatic because it
affects a large area, occurs on all of a sudden and
unpredictable. I reside in Gulf, Kuwait. 5 days ago, there was a
major earthquake in Tehran, Iran. Because of that earthquake
even some of the place in Kuwait trembled. It was e 6.2 on the
richter scale in Iran and a 1.8 in Kuwait. Most earthquakes are
minor tremors. Larger earthquakes usually begin with slight
tremors but rapidly take the form of one or more violent
shocks, and end in vibrations of gradually diminishing force
called aftershocks. The subterranean point of origin of an
earthquake is called its focus; the point on the surface directly
above the focus is the epicenter. The magnitude and intensity
of an earthquake is determined by the use of scales, e.g., the
moment magnitude scale, , Richter scale, and the modified
Mercalli scale. They can cause large scale loss of life and
property and disrupts essential services such as water
supply,sewerage systems, communication and power, transport
etc.
Causes of earthquake
Earthquakes are the vibrations caused by rocks
breaking under stress. The underground surface
along which the rock breaks and moves is called a
fault plane.Earthquakes in Australia are usually
caused by movements along faults as a result of
compression in the Earth’s crust. The size or
magnitude of earthquakes is determined by
measuring the amplitude of the seismic waves
recorded on a seismograph and the distance of the
seismograph from the earthquake. These are put
into a formula which converts them to a magnitude,
which is a measure of the energy released by the
earthquake. For every unit increase in magnitude,
there is roughly a thirty-fold increase in the energy
released. For instance, a magnitude 6.0 earthquake
releases approximately 30 times more energy than
a magnitude 5.0 earthquake, while a magnitude 7.0
earthquake releases approximately 900 times more
energy than a magnitude 5.0. A magnitude 8.6
earthquake releases energy equivalent to about 10
000 atomic bombs of the type developed in World
War II. Fortunately, smaller earthquakes occur
much more frequently than large ones and most
cause little or no damage.Earthquake magnitude
was traditionally measured on the Richter scale. It is
often now calculated from seismic moment, which
is proportional to the fault area multiplied by the
average displacement on the fault. The focus of an
earthquake is the point where it originated within
the Earth. The earthquake epicentre is the point on
the Earth’s surface directly above the focus.
Effects of earthquake
Surface trembling from seismic waves often
damages buildings. Depending on the severity of
the earthquake, gas mains may break, starting
numerous fires. Foreshocks, small earthquakes that
sometimes precede the main earthquake, can be
used as a warning system that a large shock may be
on the way. Thousands of aftershocks may follow
an earthquake and can be quite destructive,
especially to those structures that have already
been weakened and damaged. Ground motion may
trigger landslides and other rapid mass‐wasting
events that result in loss of life and damage to
buildings. A mass‐wasting variation is a landslide by
liquefaction, in which water‐soaked sediment
moves downslope like a slurry. Buildings that were
built on solid sediment may sink if liquefaction
occurs.
Rocks can be permanently displaced during an
earthquake. Fault blocks may move vertically,
forming a new scarp along the fault plane.
Horizontal movement can tear apart roads,
pipelines, and any other structures that are built
across the fault zone. Displacement rarely exceeds
about 7 meters. If the sea floor suddenly shifts
upward or downward, the sudden displacement of
water results in seismic sea waves, or tsunamis.
Unlike even the greatest storm waves, tsunamis can
be up to 90 meters high and move at speeds of up
to 400 miles per hour. Tsunamis have wavelengths
that can be as long as 160 kilometers and the water
does not quickly withdraw from the coast after the
tsunami breaks. The water continues to rise for up
to ten minutes until the long wavelength has passed
through, resulting in widespread coastal damage.
The other effects of earthquake are, deformed
ground surface, damage to man made structures,
damage to towns and cities, loss of human and
animal life, devastating fires, landslides, flash
floods, tsunamis, sandblows, faults The main
damage is caused to human, animal life and damage
to properties. Earthquakes cause a lot of
devastation, thereby causing great loss of life and
property.
Case study
Location:
Haiti is a small island located in the Caribbean,
South East of the USA and East of Cuba. Its capital
city is Port-au-Prince.
The earthquake was caused by the North American
Plate sliding past the Caribbean Plate at a
conservative plate margin. Both plates move in the
same direction, but one moves faster than the
other. The pressure that was built up because of
the friction between the 2 plates was eventually
released causing a magnitude 7 earthquake on the
Richter Scale with an epicentre 16 miles West of
Port-au-Prince and a shallow focus of 5 miles. The
earthquake struck at 16:53 (4:53pm) local time on
Tuesday 12 January 2010. The effects were: 316,000
people were killed and 1 million people were made
homeless. 3 million people were affected by the
earthquake. 250,000 homes and 30,000 other
buildings, including the President’s Palace and 60%
of government buildings, were either destroyed or
badly damaged. Hospitals and schools were badly
damaged, as was the airport’s control tower. The
main prison was destroyed and 4,000 inmates
escaped. The resopnses were: $100 million in aid
given by the USA and $330 million by the European
Union, 810,000 people placed in aid camps, 115,000
tents and 1,000,000 tarpaulin shelters were
provided, Water and sanitation eventually supplied
for 1.7 million people.
Conclusion
We cannot stop earthquake, but we can learn more,
in hopes of discovering ways to protect ourselves
from them. There are a few ways we could help
prevent some damage of earthquake in future.
Many buildings are constructed in areas of
earthquake risk. If a building is being constructed in
a city that has experienced the earthquakes, new
plans and building are to absorb the shock of
earthquake. Another easy safety thing for
earthquakes is for the government of the city to
invest in a proper seismograph centre, and make
sure there is always at least 1 person monitoring it
in case of an earthquake. Simple precautions are
the most effective ways to minimize earthquake
damages.
Bibliography
The same thing what I have written for my
earthquake project and my book also helped
‘’Earthquake and its effects’’
The end