An earthquake is a sudden, rapid shaking of the earth caused by the breaking and shifting of rock beneath the earth’s surface. Earthquakes can strike suddenly, without warning, and they can occur at any time of the year, day or night. Most tremors are west of the Rocky Mountains. However, forty-five states and territories in the United States are at moderate to very high risk of earthquakes, and they are located in every region of the country. There are two primary "hot spots" for earthquakes in the central United States that will impact Illinois, specifically in the south and southeastern parts of the state.
- New Madrid Seismic Zone lies within the central Mississippi Valley, from Cairo, Illinois, through southeastern Missouri, western Kentucky, western Tennessee, and northeast Arkansas. The epicenter of the zone is located just west and northwest of Memphis, Tennessee.
- Wabash Valley Seismic Zone, in southeastern Illinois and southwestern Indiana, is capable of producing ‘New Madrid’ size earthquake events. The epicenter of the zone is located between Mt. Vernon, Illinois, and West Franklin, Indiana (in Posey County).
If indoors:
- Stay inside.
- Take cover under a piece of heavy furniture or against an inside wall and hold on.
- The most dangerous thing to do during an earthquake is to try to leave the building. Objects can fall on you.
If outdoors:
- Move into the open, away from buildings, streetlights and utility wires.
- Once in the open, stay there until the shaking stops.
If in a moving vehicle:
- Move to a clear area away from buildings, trees, overpasses, or utility wires.
- Stop quickly and stay in the vehicle.
- Once the shaking has stopped, proceed with caution.
- Avoid bridges or ramps that might have been damaged by the quake.
After an earthquake, remain cautious. Aftershocks are not uncommon.