Transcript Plate Tectonics - twpunionschools.org

• The energy from an earthquake is released as seismic
waves, that travel through Earth’s crust from the focus
causing the ground to shake.
• P waves – come first, compress and expand
• S waves – come second, side to side
• Surface waves- move along the surface, causes severe ground movements
• Mercalli scale – measures damage, often gives
multiple ratings
• Richter Scale – measures magnitude, doesn’t
work well for large or distant ‘quakes
• Moment Magnitude Scale – measures energy
released, works well for all earthquakes
• Shaking / Aftershocks – destroys buildings, roads, etc.
• Liquefaction (when loose soil mixes with water to create mud) –
can cause buildings to sink and pull apart.
• Landslides/Avalanche (shaking causes rocks/soil or ice/snow
to move down mountains)
• Tsunamis – Earthquakes that occur in the ocean can cause
large waves to form
• Most earthquakes occur near plate boundaries
along faults, but they can occur in the middle of
a plate too.
• Drop, cover and hold (protect yourself from falling items),
• If you are inside: go under sturdy objects if possible – away
from windows or things that can fall on you
• If you are outside: move to an open area – avoid trees, power
lines, buildings..
• Have an emergency supply kit (food, water, flashlight, radio..)
• Design safer buildings, have automatic shut off valves for
utilities, secure all furniture and wall hangings