A report about earthquakes. Inside this powerpoint are: the meaning of earthquakes, types of plate movement, and how does an earthquake occur. Have Fun!

2. An earthquake (also known as a
quake, tremor or temblor) is the
result of a sudden release of energy
in the Earth's crust that creates
seismic waves. The seismicity,
seismism or seismic activity of an
area refers to the frequency, type
and size of earthquakes experienced
over a period of time.

3. At the Earth's surface,
earthquakes manifest themselves by
shaking and sometimes displacement
of the ground. When the epicenter of a
large earthquake is located offshore,
the seabed may be displaced
sufficiently to cause a tsunami.
Earthquakes can also trigger
landslides, and occasionally volcanic
activity.

4. In its most general sense, the
word earthquake is used to describe any
seismic event — whether natural or
caused by humans — that generates
seismic waves. Earthquakes are caused
mostly by rupture of geological faults,
but also by other events such as
volcanic activity, landslides, mine blasts,
and nuclear tests. An earthquake's point
of initial rupture is called its focus or
hypocenter. The epicenter is the point at
ground level directly above the
hypocenter.

6. -Convergent plate boundaries
are locations where lithospheric plates are moving
towards one another. The plate collisions that occur in
these areas can produce earthquakes, volcanic activity
and crustal deformation. In plate tectonics, a
convergent boundary, also known as a destructive plate
boundary (because of subduction), is an actively
deforming region where two (or more) tectonic plates
or fragments of the lithosphere move toward one
another and collide. As a result of pressure, friction,
and plate material melting in the mantle, earthquakes
and volcanoes are common near convergent
boundaries.
Convergent Plate Movement

7. When two plates move towards one another, they
form either a subduction zone or a continental
collision. This depends on the nature of the plates
involved. In a subduction zone, the subducting plate,
which is normally a plate with oceanic crust, moves
beneath the other plate, which can be made of either
oceanic or continental crust. During collisions
between two continental plates, large mountain
ranges, such as the Himalayas are formed.

8. - Divergent plate boundaries are locations
where plates are moving away from one another. This
occurs above rising convection currents. The rising current
pushes up on the bottom of the lithosphere, lifting it and
flowing laterally beneath it. This lateral flow causes the
plate material above to be dragged along in the direction of
flow. At the crest of the uplift, the overlying plate is
stretched thin, breaks and pulls apart.
Divergent Plate Movement

9. - Transform Plate Boundaries
are locations where two plates slide past one another.
The fracture zone that forms a transform plate
boundary is known as a transform fault. Most transform
faults are found in the ocean basin and connect off sets
in the mid-ocean ridges. A smaller number connect
mid-ocean ridges and subduction zones.
Transform plate movement

10. o Earthquakes develop in the crust of
the earth. The crust involves the
earth's surface, submarine levels,
down to the ocean floors. The inner
part of the earth contains massive
energy. Some of this energy
escapes through cracks and other
volcanic activity, but the bulk of it is
stored within the earth’s inner part,
contained in the crust.

11. o The earth’s outer crust is held
in place like a completed jigsaw
puzzle, with rough edges and
lines. The energy stored here
causes the pieces to slide,
glide, knock and move around
each piece. These pieces best
describe what we call ‘Tectonic
plates’

12. o After a period of time, the
built up energy and
movement causes huge
tension in the plates, and
there is massive pressure on
the fault lines. This intense
pressure resulting from
energy build up causes the
fault lines give way, and
plates move over, against or
apart from each other.

13. It is important
to note that
there is usually
a very thick
natural cover
(earth and
vegetation)
which makes
fault lines
obscure.
There is an earthquake at this point. In the form of
seismic waves (like water ripples) the escaping energy
radiates outward from the fault in all directions. The
seismic waves shake the earth as they move through it.
When the waves reach the earth’s surface, they shake
the ground and anything on it, tearing down houses and
structures.