Earthquake
Hazards and
Safety
CH 5 Prentice Hall
p.154-159
How Earthquakes Damage
• Severe shaking produced
by seismic waves can
damage or destroy
buildings and bridges.
• Topple utility poles
• Fracture gas and water
mains.
• S-Waves – side to side and
up/down motion can tear a
building apart.
Local Soil Conditions
• Loose soil shakes more violently than
surrounding rock.
• A house built on solid rock will shake less
than a house build on sandy soil.
Liquefaction
• Occurs when the violent shaking suddenly
turns loose, soft soil into liquid mud.
– Likely where soil is full of moisture.
– Buildings sink and pull apart.
– Can trigger landslides.
Aftershocks
• Smaller earthquakes
that follow large
earthquakes.
• Up to 1,000 per day
can strike
• May strike hours,
days or months later.
Tsunamis
• Huge ocean waves caused by underwater
earthquakes or landslides.
Tsunamis
• Displaces water and
forms a large ocean
wave.
– Waves travel at speeds
up to 750km/h or
500mph.
– Wave height is low until
it reaches land.
• Six story building (30ft)
• Threatens coast lines.
2004 Tsunami
Making Buildings Safer
• To reduce damage
new buildings must be
made stronger and
more flexible.
• Older buildings must
be modified to
withstand stronger
quakes.
Choice of Location
• Steep slopes- pose the
danger of landslides.
• Filled land (loose soil)
can shake violently
• Avoid building near
faults.
Construction Methods
• Anchor buildings and
road supports into
solid rock below.
• Base-isolated buildings
– Rests on shock
absorbing rubber pads
or springs.
– Allows the building to
move back and forth
gently.
Protecting Yourself
• Most danger is due to
falling objects.
• Stop, Cover and Hold
• Stay along an inner wall
and cover your head and
neck.
Protecting Yourself
• Avoid windows, mirrors and furniture that
may fall over.
• Make an earthquake kit- with first aid
supplies, canned food and water.
Protecting Yourself
• If outside– Move to an open area away
from falling objects:
• Power lines
• Trees
• Buildings
– Sit down to avoid being
thrown down.
Earthquake Safe House
Earthquake Supplies
Earthquake Quizzes