Earthquakes

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What is it?

A sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action. The intensity of earthquakes is expressed by the Richter scale, with destructive earthquakes generally measuring between about 7 and 9.

What’s the Risk?

There are more than 200 known, potentially active faults within Colorado's complex geological structures. In addition to known faults, seismograph instruments have recorded seismic activity in other areas of Colorado where earthquakes have been felt, but where faults were not visible to geologists.

The largest earthquake in all of Colorado's history took place on November 7, 1882 and the epicenter was described as "west of Fort Collins." It was estimated to be a magnitude 6.6 on the Richter Scale, and was the first recorded earthquake to cause damage in Denver. A quake of such magnitude occurring in Fort Collins today would be a catastrophic event.

Much of Colorado's infrastructure could be damaged in an earthquake – utility lines, highways, bridges, dams, railways, etc.

How Should I Prepare?

Before an Earthquake:

  • Fasten shelves and heavy items securely to walls.
  • Place large or heavy objects on lower shelves.
  • Store breakable objects low.
  • Secure cabinets with latches.
  • Brace overhead light fixtures and top heavy objects.
  • Locate safe spots in each room under a sturdy table or against an inside wall. Reinforce this information by moving to these places during each drill.

During an Earthquake:

  • Drop, Cover and Hold On. Minimize your movements. If you are indoors, stay there until the shaking has stopped and you are sure exiting is safe.
  • If Indoors:
    • Drop to the ground; take cover by getting under a sturdy table or other piece of furniture; and hold on until the shaking stops. If there isn’t a table or desk near you, cover your face and head with your arms and crouch in an inside corner of the building.
    • Stay inside until the shaking stops and it is safe to go outside. Do not exit a building during the shaking. Research has shown that most injuries occur when people inside buildings attempt to move to a different location inside the building or try to leave.
    • Stay away from glass, windows, outside doors and walls, and anything that could fall, such as lighting fixtures or furniture.
    • Do not use a doorway except if you know it is a strongly supported, load-bearing doorway and it is close to you. Many inside doorways are lightly constructed and do not offer protection.
    • Do not use the elevators.
    • Be aware that the electricity may go out or the sprinkler systems or fire alarms may turn on.
  • If Outdoors:
    • Stay there. Move away from buildings, streetlights, and utility wires. The greatest danger exists directly outside buildings, at exits and alongside exterior walls.
  • If in a Moving Vehicle:
    • Stop as quickly as safety permits and stay in the vehicle. Avoid stopping near or under buildings, trees, overpasses, and utility wires.
    • Proceed cautiously once the earthquake has stopped. Avoid roads, bridges, or ramps that might have been damaged by the earthquake.

After an Earthquake:

  • When the shaking stops, look around to make sure it is safe to move. Then exit the building.
  • Expect aftershocks. These secondary shockwaves are usually less violent than the main quake but can be strong enough to cause additional damage to weakened structures and can occur in the first hours, days, weeks, or even months after the quake.
  • Stay away from damaged areas. Stay away unless your assistance has been specifically requested by police, fire, or relief organizations. Return home only when authorities say it is safe.
  • Be careful when driving after an earthquake and anticipate traffic light outages.
  • Open cabinets cautiously. Beware of objects that can fall off shelves.