Earthquakes - General
An earthquake is the shaking or trembling of the crust of the earth, caused by underground volcanic forces or by breaking and shifting of rock beneath the surface. The actual movement of the earth, frightening as it is, seldom is a direct cause of death or injury. The earth usually does not yawn open, gulp down a neighborhood, and slam shut. The earth movement, however, can cause buildings and other structures to shake or collapse. Most casualties result from falling objects and debris, splintering glass, and fires.
- 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.
- 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.
- Fault: The fracture across which displacement has occurred during an earthquake. The slippage may range from less than an inch to more than ten yards in a severe earthquake.
- Magnitude: The amount of energy released during an earthquake, which is computed from the amplitude of the seismic waves. A magnitude of 7.0 on the Richter Scale indicates an extremely strong earthquake. Each whole number on the scale represents an increase of about 30 times more energy released than the previous whole number represents. Therefore, an earthquake measuring 6.0 is about 30 times more powerful than one measuring 5.0.
- 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.
Before an Earthquake
- Store water and food supply.
- Organize a 72-hour portable emergency kit.
- Bolt down or provide strong support for appliances.
- Consider earthquake insurance.
- Fasten shelves securely to the walls.
- Place large or heavy objects on the lowest shelves.
- Store breakable items such as bottled foods, glass, and china in low, closed cabinets with latches.
- Hang heavy items such as pictures and mirrors away from beds, couches, and anywhere people sit.
- Brace overhead light fixtures.
- Repair defective electrical wiring and leaky gas connections which are potential fire risks.
- Secure water heaters by strapping them to the wall studs and bolting them to the floor.
- Repair any deep cracks in the ceilings or the foundations and get expert advice if there are signs of structural defects.
- Store weed killers, pesticides, and flammable products securely in closed cabinets with latches.
- Contact your local emergency management office or American Red Cross chapter for more information on earthquakes.
- Teach children how and when to call 9-1-1, police, or fire department and which radio station to tune to for emergency information.
- Plan and practice a family drill at least once a year.
- Prepare your vehicle with a 72-Hour Kit.
- Take a first aid course.
Have Disaster Supplies on Hand
- Flashlight and extra batteries.
- Portable battery-operated radio and extra batteries.
- First aid kit and manual.
- Emergency food and water.
- Non-electric can opener.
- Essential medicines.
- Cash and credit cards.
- Sturdy shoes.
Develop an Emergency Communication Plan
- In case family members are separated from one another during an earthquake (a real possibility during the day when adults are at work and children are at school), develop a plan for reuniting after the disaster.
- Ask an out-of-state relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone in the family knows the name, address, and phone number of the contact person.
During an Earthquake
- Stay inside and find protection in a doorway, or crouch under a desk or table, away from windows, glass, brick walls, and chimneys.
- Don't run through or near buildings as the greatest danger from falling debris is just outside doorways and close to outer walls.
- Don't use candles, matches, or other open flames either during or after the tremor.
- Douse all fires.
- Stay outside.
- Stand away from buildings, trees, telephone lines, and electrical lines.
On the Road:
- Drive away from under-passes and over-passes.
- Stop in a safe area as quickly as safety permits.
- Stay in your vehicle.
- When you drive on, watch for hazards created by the earthquake, such as fallen objects, downed electric wires, or broken or undermined roadways.
In an Office Building:
- Stay next to a pillar or column, or under a heavy table or desk.
- Do not use the elevators.
- Be aware that the electricity may go out or the sprinkler systems or fire alarms may turn on.
If Trapped Under Debris:
- Do not light a match.
- Do not move about or kick up dust.
- Cover your mouth with a handkerchief or clothing.
- Tap on a pipe or wall so rescuers can locate you.
- Use a whistle if one is available.
- Shout only as a last resort as shouting can cause you to inhale dangerous amounts of dust.
After an Earthquake
- Expect aftershocks, which are secondry shockwavs that are usually less violent than the main quake but can be strong enough to do additional damage to weakened structures and can occur in the first hours,f days, weeks, or even months after the first quake.
- Check for injuries and provide first aid.
- Do not attempt to move seriously injured persons unless they are in immediate danger of further injury.
- Do not use matches or open flames until you are sure there are no gas leaks.
- Don't turn light switches off and on -- sparks created by the switch contacts can ignite gas fumes.
- Check for fires; gas, water, sewage breaks; downed electric lines; building damage and potential problems during after shocks, such as cracks around fireplace and foundation. Turn off interrupteded utilities as necessary at the main valves.
- If water pipes are damaged, shut off the supply at the main valve.
- Emergency water may be obtained from such sources as hot water tanks, toilet tanks, and melted ice cubes.
- Check to see that sewage lines are intact before permitting continued flushing of toilets.
- Check chimneys for cracks and damage -- unnoticed damage could lead to a fire. The initial check should be made from distance; approach chimneys with great caution.
- Open cabinets cautiously as objects can fall off of shelves.
- Stay out of severly damaged buildings; aftershocks can shake them down.
- Do not heed or spread rumors; they often do great harm following disasters.
- Stay off the telephone, except to report an emergency.
- Turn on your radio or television to get the latest emergency information.
- Don't go sightseeing.
- Respond to reuests for assistance from police, fire fighting, and relief organizations, but do not go into damaged areas unless your assistance has been requested.
- Cooperate fully with local authorities.
- Clean up dangerous spills.
- Wear shoes and leather gloves.
- As soon as possible, notify family that you are safe.
- In public buildings, follow evacuation procedures immediately and return only after the building has been declared safe by the appropriate authorities.
- If in a coastal area, be aware of possible tsunamis which are seismic sea waves