Earthquakes
EarthquakesGenevieve LawrenceAn earthquake is a sudden movement
or tremor of the earths crust.Most earthquakes occur on plate
boundaries. (This PowerPoint will explain why.)What are
earthquakes?
DID YOU KNOW?It is estimated that there are 500,000 detectable
earthquakes in the world each year.
The deepest earthquakes normally occur at plate boundaries where
the Earths crust is being pushed into the Earths mantle. These
occur as deep as 750 km below the surface.
Although both are sea waves, a tsunami and a tidal wave are
completely unrelated. A tidal wave is a shallow water wave caused
by the gravitational interactions between the Sun, Moon and Earth.
A tsunami is a sea wave caused by an underwater earthquake or
landslide (usually triggered by an earthquake) displacing the ocean
water. This is what happened in Japan in 2010.
G
How are earthquakes measured?Earthquake magnitudes are
classified by seismologists (people who study them). They use a
scale called the Richter Scale, invented by Charles Richter which
ranges from 1-10, 1 being very weak and 7 and over being
destructive.
What causes earthquakes?The Earths crust is broken into several
enormous sections called plates. The plates float on the Earths
mantle, a layer of molten rock. They move around, but very slowly.
Often on plate boundaries, they rub together. The movement of the
plates scraping together makes the ground shake and sets off
earthquakes. In some places, Earthquakes dont just happen on land;
they can also happen in the seaWhat are the effects of
earthquakes?Earthquakes can be very destructive.Destruction of
buildings and transportation systems. Almost everything is
destroyed. The ground is covered with cracks and holes.
hIn 2010, a massive earthquake struck japan. As a result, a huge
tsunami What happened in Japan?Collage of images
