Transcript base-isolating - Madison County Schools

Bellringer
How does a seismic station determine how far
away an earthquake occurred from that station?
Earthquake Safety
Notes
Earthquake Risk
• Earthquakes are most likely at faults
along the boundary between two plates.
• The Pacific Plate and the North
American Plate meet along the Pacific
coast of the United States.
• The coasts of California, Washington,
and Alaska all have a high risk of
earthquakes.
Earthquake Risk
• The eastern United States is far from plate
boundaries. Only a few big earthquakes have
happened in the eastern United States in the
past.
• The New Madrid Fault along the Mississippi River
on the western border of Tennessee is thought to
be a failed rift system from 750 million years ago.
• The South Carolina earthquake zone is from a
fault line created during the breakup of Pangea
that stays active due to the motion of the N.
Tectonic Plate Boundaries
How Earthquakes
Cause Damage
• When an earthquake happens, seismic
waves cause the ground to shake. The
shaking can destroy buildings and
break gas and water pipes.
How Earthquakes
Cause Damage
• Sometimes the shaking turns soft soil
into mud. This is called liquefaction.
Liquefaction can make buildings sink
into the ground like quicksand.
• Actually, quicksand is a form of
liquefaction without the need of an
earthquake.
How Earthquakes
Cause Damage
• Smaller earthquakes, called
aftershocks, can follow a big
earthquake. Aftershocks add to the
damage done by the big earthquake.
• Aftershocks may strike hours, days, or
even months after the primary event.
How Earthquakes
Cause Damage
• An earthquake on the ocean floor can
cause a huge ocean wave, called a
tsunami. Tsunamis can cause a great
deal of damage along coasts.
http://www.pep.bc.ca/tsunamis/causes_2.htm
Steps to Earthquake
Safety
• If you are indoors when an earthquake
hits, you should drop down under a
sturdy table or desk. Then you should
cover your head and neck with your
arms and hold onto the table or desk.
Steps to Earthquake
Safety
• If you are outdoors when an earthquake
hits, you should move to an open area
such as a playground. You should sit on
the ground so you will not be thrown to
the ground when the earthquake
shakes.
Steps to Earthquake
Safety
• After an earthquake, you may have no
electricity or running water for a while.
Stores and roads may also be closed.
• If you live where earthquakes are likely,
you should have an earthquake kit. The
kit should include canned food, water,
and other emergency supplies.
Designing Safer
Buildings
• The main danger in earthquakes is falling
buildings and objects. To reduce danger, plywood
can be added to walls to make buildings stronger.
Tall furniture can also be attached to walls.
• Sinking due to liquefaction can be reduced by
attaching the building to solid rock beneath the
soil.
• Broken pipes can cause fires and flooding. By
making piping flexible, the pipes will bend instead
of break during an earthquake.
Designing Safer
Buildings
• Some high-rise buildings use a
technique called base-isolating. In a
base-isolated building, springs or
rubber pads are placed between the
foundation and the bottom of the
building, acting like the suspension in a
car.
http://www.rubberimpex.com/images/RubberParts/SXR
P02/PrincipleDiagramAntiEarthquakeSeismicIsolation
BuildingBaseSupportRubberBearing.gif