Earthquakes

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Oregon is one of the most beautiful places to live in the United States with its high mountains and rugged coastline. Yet the geologic forces that have made it so breathtaking also make it one of the most earthquake-prone spots in the United States.

An earthquake is the sudden, sometimes violent movement of the earth's surface from the release of energy in the earth's crust. While the threat of an earthquake may seem daunting, making a plan and identifying things you can do now to prepare can significantly reduce injuries and property damage.

The number one cause of death in an earthquake is running out of a building and being struck by falling debris! With the strict construction standards in the United States today, you are far safer staying inside a building when an earthquake occurs.

Know the Terms
  • Earthquake - A sudden slipping or movement of a portion of the earth’s crust, accompanied and followed by a series of vibrations.
  • Aftershock - An earthquake of similar or lesser intensity that follows the main earthquake.
  • Fault - The fracture across which displacement has occurred during an earthquake. The slippage may range from less than an inch to more than 10 yards in a severe earthquake.
  • Epicenter - The place on the earth’s surface directly above the point on the fault where the earthquake rupture began. Once fault slippage begins, it expands along the fault during the earthquake and can extend hundreds of miles before stopping.
  • Seismic Waves - Vibrations that travel outward from the earthquake fault at speeds of several miles per second. Although fault slippage directly under a structure can cause considerable damage, the vibrations of seismic waves cause most of the destruction during earthquakes.
  • Magnitude - The amount of energy released during an earthquake, which is computed from the amplitude of the seismic waves.
Before an Earthquake
  • Repair defective electrical wiring, leaky gas lines and inflexible utility connections. Get appropriate professional help. Do not work with gas or electrical lines yourself.
  • Bolt down and secure to the wall studs your water heater, refrigerator, furnace and gas appliances. If recommended by your gas company, have an automatic gas shut-off valve installed that is triggered by strong vibrations.
  • Place large or heavy objects on lower shelves. Fasten shelves, mirrors and large picture frames to walls. Brace high and top-heavy objects.
  • Store bottled foods, glass, china and other breakables on low shelves or in cabinets that fasten shut.
  • Anchor overhead lighting fixtures.
  • Be sure the residence is firmly anchored to its foundation.
  • Install flexible pipe fittings to avoid gas or water leaks. Flexible fittings are more resistant to breakage.
  • Locate safe spots in each room under a sturdy table or against an inside wall. Practice getting to them quickly by moving to these places during each drill.
  • Hold earthquake drills with your family members: Drop, cover, and hold on!
During an Earthquake
  • Duck, Cover, and Hold! Minimize your movements during an earthquake to a few steps to a nearby safe place. Stay indoors until the shaking has stopped and you are sure exiting is safe.
  • A dangerous earthquake myth is that you should take shelter in a doorway. Doorways are no stronger than any other part of the house and put you at risk to be struck and injured by the door or other objects. You are safer under a table.
After an Earthquake
  • Be prepared for aftershocks. These secondary shockwaves are usually less violent than the main quake but can be strong enough to do additional damage to weakened structures.
  • Open cabinets cautiously. Beware of objects that can fall off shelves.
  • Stay away from damaged areas unless your assistance has been specifically requested by police, fire or relief organizations.
  • Be aware of possible tsunamis if you live in coastal areas. These are also known as seismic sea waves (mistakenly called “tidal waves”). When local authorities issue a tsunami warning, assume that a series of dangerous waves is on the way. Stay away from the beach.
  • Monitor NOAA Weather Radio All Hazards and commercial radio and TV for information and be ready to follow instructions instantly.

For additional information on earthquake preparedness, please see these guides:

FEMA B-526 - Earthquake Safety Checklist (PDF)

Living on Shaky Ground (PDF)

 

The Hazard-Specific Information section was created using information from the Federal Emergency Management Agency and American Red Cross.

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