An earthquake is caused by the sudden release of built-up energy along fault lines in the earth's crust. The Richter scale is used to measure the magnitude of earthquakes on a logarithmic scale, where each whole number increase corresponds to a tenfold increase in measured amplitude. The impact of an earthquake is characterized by its intensity of shaking and the location of its epicenter, where it originates underground. Common earthquake damage includes collapsed structures, fires, landslides, and tsunamis. Over 59% of India's land area faces moderate to severe seismic hazard, especially along the Himalayan belt where great quakes over 8.0 magnitude can occur.

1.  NAME :SRINIVAS REDDY
 BRANCH : CIVIL ENGINEERING

2. An earthquake is defined as a sudden movement of earth’s
crust or upper mantle . It caused by the movement along a
fault plane or by volcanic activity and resulting in generation
of seismic waves which can be destructive.

3.  The most common scale used for measuring an
earthquake is Richter Scale. It should be
understood that Richter scale is a logarithmic
scale. What this means is an earthquake
measuring 6.0 is 10 times more powerful than
an earthquake measuring 5.0
WHAT DO WE USE TO MEASURE EARTHQUAKES ?

4.  The impact of an earthquake (at any location) is
characterized by two primary characteristics:
1.Intensity : describes the level of shaking during an
earthquake. Higher the value higher is the
magnitude
2.Epicenter : It denotes the exact location , where the
earthquake is originated.

5. The most common kinds of loss that are caused by an
earthquake (depending on the severity) are:
 Damage to structures
 Effect of ground shaking
 Ground displacement
 Fire
 Sea activity
 Landslides

6.  Earthquakes are usually caused when rock underground
suddenly breaks along a fault. This sudden release of energy
causes the seismic waves that make the ground shake. When
two blocks of rock or two plates are rubbing against each
other, they stick a little. They don't just slide smoothly; the
rocks catch on each other. The rocks are still pushing against
each other, but not moving. After a while, the rocks break
because of all the pressure that's built up. When the rocks
break, the earthquake occurs. During the earthquake and
afterward, the plates or blocks of rock start moving, and they
continue to move until they get stuck again. The spot
underground where the rock breaks is called the focus of the
earthquake. The place right above the focus (on top of the
ground) is called the epicentre of the earthquake.

7.  The Earth's crust is broken up into pieces called plates. Heat
rising and falling inside the mantle creates convection
currents generated by radioactive decay in the core. The
convection currents move the plates. Where convection
currents diverge near the Earth's crust, plates move apart.
Where convection currents converge, plates move towards
each other. The movement of the plates, and the activity
inside the Earth, is called plate tectonics.
 Plate tectonics cause earthquakes and volcanoes. The point
where two plates meet is called a plate boundary.
Earthquakes and volcanoes are most likely to occur either on
or near plate boundaries.

8.  Collapsing buildings, walls, bridges, falling furniture or
objects, shattering glass windows and mirrors.
 Falling electricity lines
 Rock slides and/or landslides on mountains and hillsides
 Floods caused by the collapse of dam walls
 Tsunamis
 Liquefaction

9. EARTH QUAKE HAZARDS IN INDIA

10.  During the last 15 years, the country has experienced 10
major earthquakes that have resulted in over 20,000 deaths.
As per the current seismic zone map of the country (IS 1893:
2002), over 59 per cent of India’s land area is under threat
of moderate to severe seismic hazard.
 In fact, the entire Himalayan belt is considered prone to great
earthquakes of magnitude exceeding 8.0 .
EARTH QUAKE HAZARDS IN INDIA

11. •Latest version of seismic zoning map of India given in the earthquake
resistant design code of India [IS 1893 (Part 1) 2002] assigns the earth
quake zoning map of India divides India into 4seismic zones (Zone 2,
3, 4 and 5)
Zones according to is 1893 (part 1) 2002:
Zone 5:
It covers the areas with the highest risks zone that suffers earthquakes
of intensity MSK IX or greater. The region of Kashmir, the western
and central Himalayas, North and Middle Bihar, the North-East Indian
region and the Rann of Kutch ,the Andaman and Nicobar group
islands fall in this zone.

12. Zone 4
 This zone is called the High Damage Risk Zone and covers
areas liable to MSK VIII. The IS code assigns zone factor of
0.24 for Zone 4. The Indo-Gangetic basin, Delhi, Jammu
and Kashmir ,In Maharashtra, the Patan area ,In Bihar the
northern part of the state like- Raksaul, Near the border of
India and Nepal, is also in zone no-4.
Zone 3
 The Andaman and Nicobar Islands , parts of Kashmir ,
Western Himalayas fall under this zone. This zone is
classified as Moderate Damage Risk Zone which is
liable to MSK VII. and also 7.8
Zone 2
This region is liable to MSK VI or less and is classified as
the Low Damage Risk Zone

14.  Earthquake is such a disaster, which cannot be predicted.
Thus, the only way to reduce the damages and losses due to
an earthquake is effective preparedness .
 However, in most of the countries, an earthquake occurs
once in several years, which may vary from 10 to 50 or even
100 years. Thus, obviously the priority of earthquake is
lower than other more frequent disasters like floods,
cyclones and draughts .
 Consequently, in most of the countries, earthquake disaster
remains within a dilemma of sudden occurrence versus
infrequent occurrences

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