disaster and its management-geography IX

2. INTRODUCTION
• Our country, India,due to its peculiar physical
features is one of the most ‘disaster prone’
countries in the world.
• Natural hazards are the various natural
phenomena such as earthquakes,
floods,droughts,cyclones,landslides,and
forestfires.
• Natural disasters are natural hazards that can
cause great loss of life and property.
• We can reduce disasters into hazards by taking
precautionary measures.

3. • At the times of natural disasters, the
first thing to provide help is always the
community. Therefore, we all need to
know about the disasters and
precautions for it.
• Young students are the active ,main and
helpful ones in the community. Thus,
they need proper training and a will to
help .

4. EARTHQUAKE

5. EARTHQUAKE
The shaking of the ground caused by sudden movements in
earth’s crust is called an earthquake.
The waves generated by an earthquake is called seismic
waves.
Seismology is the branch of science which deals with
earthquakes.
The scientists who study earthquakes are called seismologists.
The occurrence of an earthquake can be detected by a
sensitive instrument known as seismograph.
The intensity of the earthquake can be measured with the
help of an instrument known as the Richter scale.

6.  The place of origin of an earthquake is called it’s focus .It
lies within the earth’s crust.
 The epicenter is the place which is directly above the
focus on the surface of the earth.
 The effect of the earthquake is the strongest near the
epicenter.
 The intensity of an earthquake depends on the amount
of the energy released and is based on the direct
measurement of the size and the seismic waves
 The earthquakes intensity is measured by the help of
richterscale.
 Earthquakes are caused by the movements and collisions
in the tectonic plates which lies in the earth’s
lithosphere.
 The boundaries of the tectonic plates are the zones
where earthquakes are mostly likely to occur. These are
known as seismic or fault zones

8. PRECAUTION FOR EARTHQUAKES
• Leave buildings and move to open areas.
• Learn the basic first aid functions.
• Stay away from windows ,shelves,mirrors,fans
etc…. during or after an earthquake.
• If trapped in a building, remain close to an
interior wall and protect your head with your
arms.
• Lifts should be avoided.
 If outdoors, stay away from trees, signboards,
buildings, poles and electric wires.
 Help others according to their needs

15. After affects of

18. TSUNAMI
• Tsunami is a Japanese word which means
harbor waves.
• A tsunami can be of height 20-30 meters
when it hits the shore.
• Tsunami is not one giant wave but a series of
waves that comes ashore at intervals of 10-45
minutes.
• A tsunami occurs when large amount of water
is displaced this can be caused by under sea
volcanic eruptions and earthquakes.

19. • The speed of tsunamis are about500-100metres.But
It reduces as it approaches the land.
• A huge tsunami can crush house and other
structures. large objects such as ships can be
pushed several kilometers ahead
• Most deaths caused by tsunamis are due to
drowning

20. PRECAUTIONS AGAINST
TSUNAMIS
•If you experiences an earthquake that lasts for about 20 seconds or
longer when you happen to be in a coastal area, move to higher
grounds immediately.
•In some cases ,the sea water may recede up to 800m from the coast
.Don't enter this temporarily dry area, as sea water will come back
soon.
•The areas of great risk are less than 10m above the sea level and
within 2km from the coasts. if you are in this zone, move out of this
zone immediately.
•The tsunami warning systems should be installed in high-risk zones.
•Carry a first aid kit with you as soon as you start to evacuate the danger
zone.
•Help other people according to their needs.

26. CONCLUSION
 Natural hazards are the various natural phenomena such as
earthquakes, floods,droughts,cyclones,landslides,and forest fires.
 Natural disasters are natural hazards that can cause great loss of
life and property
 The shaking of the ground caused by sudden movements in earth’s
crust is called an earthquake.
 The waves generated by an earthquake is called seismic waves.
 Seismology is the branch of science which deals with earthquakes.
 The scientists who study earthquakes are called seismologists.
 The occurrence of an earthquake can be detected by a sensitive
instrument known as seismograph.
 The intensity of the earthquake can be measured with the help of
an instrument known as the Richter scale.

27.  The place of origin of an earthquake is called it’s focus .It lies
within the earth’s crust.
 The epicenter is the place which is directly above the focus on
the surface of the earth
 Tsunami is a Japanese word which means harbor waves.
 A tsunami occurs when large amount of water is displaced this
can be caused by under sea volcanic eruptions and
earthquakes.
 As soon you are informed of an approaching disaster take
precautionary measures for it and evacuate out of the danger
zone

30. THE RICHTER SCALE
• The Richter scale was developed by American
scientist CHARLES F RICHTER in 1935 in order to
measure the intensity of the earhquakes.
• Number 1to10 relate to the energy that the quake
releases.
• Those of magnitude 2 are not felt. A magnitude5
quake can cause major damage. Above 8 and the
effects can be spread over hundred of miles.
• On the Richter scale, each step is a 30 fold increase in
energy. So a magnitude 9 quake is 8,00,000 times
bigger than a magnitude 5 quake.

31. CHARLES F RICHTER

32. THE RICHTER SCALE
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