2. Earthquakes
Earthquakes are shaking or vibration of the
earth's crust. They make the land move and
the effects of earthquake vary upon the
magnitude and intensity. Earthquakes occur
every now and then all round the world,
except in some place places which
earthquakes occur rarely. The devastation of
cities and towns is one of the effects of
earthquake. Landslides and Avalanches are
caused by movement of earthquakes. Huge
rocks come tumbling down the mountains
sometimes blocking the path of rivers. This
can cause floods. Houses are broken down
by earthquakes. A huge Tidal wave called
Tsunami which is derived from a Japanese
word Tsu meaning harbor and Nami meaning
wave. These tidal waves from the sea
towards the land causing huge floods.
4. The Ten Largest Earthquakes Since 1900
Location Date Magnitude
1. Chile May 22, 1960 9.5
2. Prince William Sound, Alaska March 28, 9.2
1964
3. Andreanof Islands, Aleutian Islands March 9, 1957 9.1
4. Kamchatka Nov. 4, 1952 9.0
5. Off western coast of Sumatra, Dec. 26, 2004 9.0
Indonesia
6. Off the coast of Ecuador Jan. 31, 1906 8.8
7. Rat Islands, Aleutian Islands Feb. 4, 1965 8.7
8. Northern Sumatra, Indonesia March 28, 8.7
2005
9. India-China border Aug. 15, 1950 8.6
10 Kamchatka Feb. 3, 1923 8.5
.
5. 1906 San Francisco
The San Francisco earthquake of 1906
was a major earthquake that struck San
Francisco, CA and the coast of Northern
California at 5:12 A.M. on Wednesday,
April 18, 1906. The most widely accepted
estimate for the magnitude of the
earthquake is a moment magnitude.
At the time, 376 deaths were reported; the
figure was fabricated by government officials
who felt that reporting the true death toll
would hurt real estate prices and efforts to
rebuild the city
6. Predicting Earthquakes
Because of their devastating
potential, there is great interest in
predicting the location and time of
large earthquakes. Although a great
deal is known about where
earthquakes are likely, there is
currently no reliable way to predict
the days or months when an event
will occur in any specific location.
In the past there have been many
earthquakes that led to massive loss of life
and property, and they all struck with little
or no warning. Japan has probably the
most advanced earthquake detection
system in the world, yet was caught
completely unawares by the Kobe
Earthquake of 1995.
7. Earthquakes proof structure
An earthquake-proof building is a
building that has been built to survive an
earthquake. The building is built with
special technology that has materials
made in earthquake areas. No building,
however, can be made 100% safe and
building earthquake proof structures to
be more effective is just trial and error.
8. Primary and secondary waves
Primary waves are longitudinal waves that push and
pull the earth. They are the fastest body wave,
averaging speeds of about 6 km/s, so arrive first.
Secondary waves are transverse waves,
which make the earth shake from side to side.
Slower than Primary waves, they average about
4 km/s so arrive second.
9. Created by- sarim anjum
Class-X b
roll no- 22
• Under the noble guidence of – P S Topo
mam.
10. Created by- sarim anjum
Class-X b
roll no- 22
• Under the noble guidence of – P S Topo
mam.
