EARTHQUAKE DAMAGE CAN
BE REDUCED
Earthquakes are
most dangerous
near areas where
people live.
Deaths and
injuries are not
caused by
movement of the
ground, but
buildings collapsing
and fires.
Earthquake damage can be
reduced
A powerful earthquake
(magnitude of 8 or
higher) can release
more energy than 1
million weak
earthquakes.
The first scale of
earthquake magnitude
was developed by
Charles Richter and
Beno Gutenburg
Earthquake damage can be
reduced
The Richter scale measures how fast
the ground moves at a seismic station
Earthquake damage can be
reduced
Most scientists
currently use the
moment magnitude
scale
Both ricther and
moment scale show a
top value of 10, but
neither has a maximum
value.
The moment
magnitude scale is
more accurate for
larger earthquakes
Earthquake damage can be
reduced
Movement of blocks of
rock along a fault on
either side can raise,
lower or tilt the ground
surface(This can
collapse buildings)
Many buildings collapse
and in the process gas
lines,power lines, and
water lines can be
damaged
Earthquake damage can be
reduced
In the San Francisco earthquake of
1906, 90% of the buildings collapsed
Earthquake damage can be
reduced
Earthquakes can also cause landslides
to occur
A landslide is movement of rocks and
soil down a hill or a mountain
Structures either sink with the soil or
flow away with it
Earthquake damage can be
reduced
A tsunami can also occur as a result of
an earthquake, volcanic eruption or
landslide.
A tsunami is a
water wave that can
rise more than a
20 story building
Earthquake damage can be
reduced
A tsunami can be a single wave or
several waves of different heights
In deep water a
tsunami can reach
speeds of about
430 mph
Earthquake damage can be
reduced
In 1946 a earthquake
hit Alaska, a tsunami
resulted and the
highest wave was 55
feet high and it killed
159 people
The Pacific Tsunami
Warning center was
established in hawaii
in 1949
Earthquake damage can be
reduced
Scientists havent figured out
earthquakes similar to the weather
they can only make longterm
predictions
Scientists study stress along fault
lines
Earthquake damage can be
reduced
Signs that give scientists clues are:
Tilts or changes in rock
Slow movement or stretching in rock
The development of small cracks in
the ground
Earthquake damage can be
reduced
The best way to
prevent death and
injuries is to build
structures meant to
withstand some
earthquakes
Base isolators are
built into buildings,
they are flexible an
absorb the shock
Earthquake damage can be
reduced
Buildings are also
built on a moat which
will let the building
shake more gently
Cross braces are also
added to help the
structure keep it’s
shape while shaken