this is something i made for my school project.... hope u guys benefit frm it.... =) =)

2. Today we’ll learn the
answers to:
1. What are earthquakes?
2. How do earthquakes occur?
3. What are the effects of
earthquake?
4. How can we protect ourselves
from earthquakes?
5. Chilean earthquake 1960

3. HATAREEARTHQUAKES

4. An earthquake is the result of a sudden release of energy in
the Earth's crust that creates seismic waves. The seismic
activity of an area refers to the frequency, type and size of
earthquakes experienced over a period of time.
Earthquakes are measured using observations from
seismometers. The moment magnitude is the most common
scale on which earthquakes larger than approximately 5 are
reported for the entire globe. The more numerous
earthquakes smaller than magnitude 5 reported by national
seismological observatories are measured mostly on the
local magnitude scale, also referred to as the Richter scale.
These two scales are numerically similar over their range of
validity. Magnitude 3 or lower earthquakes are mostly almost
imperceptible or weak and magnitude 7 and over potentially
cause serious damage over larger areas, depending on their
depth.

8. HOW DO EARTHQUAKES
OCCUR?
Most earthquakes are causally related to compressional or
tensional stresses built up at the margins of the huge moving
lithospheric plates that make up the earth's surface. The
immediate cause of most shallow earthquakes is the sudden
release of stress along a fault, or fracture in the earth's crust,
resulting in movement of the opposing blocks of rock past
one another. These movements cause vibrations to pass
through and around the earth in wave form, just as ripples
are generated when a pebble is dropped into water. Volcanic
eruptions, rockfalls, landslides, and explosions can also
cause a quake, but most of these are of only local extent.
Shock waves from a powerful earthquake can trigger smaller
earthquakes in a distant location hundreds of miles away if
the geologic conditions are favorable.

10. • Ground rupture
Shaking and ground rupture are the main effects created by earthquakes,
principally resulting in more or less severe damage to buildings and other rigid
structures.
•Floods
Floods may be secondary effects of earthquakes, if dams are damaged. Earthquakes
may cause landslips to dam rivers, which collapse and cause floods.
•Fires
Earthquakes can cause fires by damaging electrical power or gas lines.
•Avalanches and landslides
Earthquakes, along with severe storms, volcanic activity, coastal wave attack, and
wildfires, can produce slope instability leading to landslides, a major geological
hazard.
•Loss of life and damage to properties
An earthquake may cause injury and loss of life, road and bridge damage, general
property damage, and collapse or destabilization (potentially leading to future
collapse) of buildings. The aftermath may bring diseases and lack of basic
necessities such as food and clean drinking water.

11. Loss of life and damage to
properties

12. Fires

13. Tsunamis and floods

14. Avalanches and landslides

15. HOW CAN WE PROTECT
OURSELVES FROM
EARTHQUAKES?If you are…
•Indoors: Drop, cover, and hold on.Drop to the floor, take cover under a sturdy desk or table, and hold on to it
firmly. Be prepared to move with it until the shaking stops. If you are not near a desk or table, drop to the floor against the interior wall
and protect your head and neck with your arms. Avoid exterior walls, windows, hanging objects, mirrors, tall furniture, large appliances,
and kitchen cabinets with heavy objects or glass. Do not go outside!
•In bed: If you are in bed, hold on and stay there, protecting your head with a pillow. You are less likely to be injured staying
where you are. Broken glass on the floor has caused injury to those who have rolled to the floor or tried to get to doorways.
•Outdoors: Move to a clear area if you can safely do so; avoid power lines, trees, signs, buildings, vehicles, and other hazards.
•Driving: Pull over to the side of the road, stop, and set the parking brake. Avoid overpasses, bridges, power lines, signs and other
hazards. Stay inside the vehicle until the shaking is over. If a power line falls on the car, stay inside until a trained person removes the
wire.
•In a high-rise: Drop, cover, and hold on. Avoid windows and other hazards. Do not use elevators. Do not be surprised if
sprinkler systems or fire alarms activate.
•In a stadium or theater: Stay at your seat and protect your head and neck with your arms. Don't try to leave
until the shaking is over. Then walk out slowly watching for anything that could fall in the aftershocks.
•Below a dam: Dams can fail during a major earthquake. Catastrophic failure is unlikely, but if you live downstream from a
dam, you should know flood-zone information and have prepared an evacuation plan.
> If you are at the beach, move to higher ground immediately - no matter how small the earthquake.
> If you are in a tsunami hazard zone and the earthquake is very strong, immediately
gather your family members, grab your tsunami disaster kit, and WALK to a safe area.
> If evacuation is impossible, go to the upper floor of a sturdy building or climb a tree. This should only be a last resort.
> Do not wait for an official warning.

17. Chilean earthquake 1960
The 1960 Valdivia earthquake or Great Chilean Earthquake of Sunday, 22 May 1960
was the most powerful earthquake ever recorded, rating 9.5 on the moment
magnitude scale. It occurred in the afternoon (19:11 GMT, 15:11 local time), and
lasted approximately 10 minutes. The resulting tsunami affected southern Chile,
Hawaii, Japan, the Philippines, eastern New Zealand, southeast Australia, and the
Aleutian Islands.
The epicenter was near Lumaco , approximately 570 kilometres (350 mi) south
of Santiago, with Valdivia being the most affected city. The tremor caused localised
tsunamis that severely battered the Chilean coast, with waves up to 25 meters
(82 ft). The main tsunami raced across the Pacific Ocean and devastated Hilo,
Hawaii. Waves as high as 10.7 metres (35 ft) were recorded 10,000 kilometers
(6,200 mi) from the epicenter, and as far away as Japan and the Philippines.