Print  Email

Are You Ready for Earthquakes?

Map of eathquake hazard areas in the united states

One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible aftereffects. An earthquake is a sudden movement of the earth, caused by the abrupt release of strain that has accumulated over a long time. For hundreds of millions of years, the forces of plate tectonics have shaped the earth, as the huge plates that form the earths surface slowly move over, under, and past each other. Sometimes, the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free. If the earthquake occurs in a populated area, it may cause many deaths and injuries and extensive property damage.

Know the Terms

Familiarize yourself with these terms to help identify an earthquake hazard:

Earthquake A sudden slipping or movement of a portion of the earths 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 earths 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. 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.

Take Protective Measures

Before an Earthquake

The following are things you can do to protect yourself, your family, and your property in the event of an earthquake:

During an Earthquake

Depending on where you are, different actions are necessary to be as protected as possible. Here are different scenarios and what you should do if you are:

Indoors:
Outdoors:
In a moving vehicle:
Trapped Under Debris:

After an Earthquake

For More Information

If you require more information about any of these topics, the following are resources that may be helpful.

FEMA Publications:

Avoiding Earthquake Damage: A Checklist for Homeowners. Safety tips for before, during, and after an earthquake

Preparedness in High-Rise Buildings. FEMA-76. Earthquake safety tips for high-rise dwellers

Learning to Live in Earthquake Country: Preparedness in Apartments and Mobile Homes. L-143. Safety tips on earthquake preparation for residents of apartments and mobile homes

Family Earthquake Safety Home Hazard Hunt and Drill. FEMA-113. How to identify home hazards; how to conduct earthquake drills

Earthquake Preparedness: What Every Childcare Provider Should Know FEMA 240. Publication for teachers and for presentation to children.