Earthquake Information

Richter magnitude scale

The Richter magnitude scale is a measurement of the amount of seismic energy released by an earthquake. Each whole number increase in magnitude is an increase of approximately 31.6 times in energy released. The following table details the magnitude scale of an earthquake and the effects it can cause.

 
Magnitude
Category
Effects of Earthquake
  Less than 2.0 Micro Microquake, not felt.
  2.0 to 2.9 Minor Generally are not felt, but are recorded.
  3.0 to 3.9 Minor Generally felt, rarely cause damage.
  4.0 to 4.9 Light Noticeable shaking and rattling, unlikely to cause significant damage.
  5.0 to 5.9 Moderate Can damage poorly constructed building, light damage to well designed buildings.
  6.0 to 6.9 Strong Can be destructive in areas up to 100 miles across.
  7.0 to 7.9 Major Can cause serious damage over larger areas.
  8.0 to 8.9 Great Can cause serious damage in areas hundreds of miles across.
  9.0 to 9.9 Great Can be devastating in areas several thousand miles across.
  10.0 and greater Great Never been recorded, strongest on record is a 9.5 quake in Chile on May 22, 1960.

What to do during an Earthquake

• If you are indoors, get under a desk or table and hang on to it, or move into a hallway or get against an inside wall. Stay clear of windows, fireplaces, and heavy furniture or appliances. Get out of the kitchen, which is a dangerous place (things can fall on you). Don't run downstairs or rush outside while the building is shaking or while there is danger of falling and hurting yourself or being hit by falling glass or debris.

• If you are outside, get into the open, away from buildings, power lines, chimneys, and anything else that might fall on you.

• If you are driving, stop, but carefully. Move your car as far out of traffic as possible. Do not stop on or under a bridge or overpass or under trees, light posts, power lines, or signs. Stay inside your car until the shaking stops. When you resume driving watch for breaks in the pavement, fallen rocks, and bumps in the road at bridge approaches.

• If you are in a mountainous area, watch out for falling rock, landslides, trees, and other debris that could be loosened by quakes.

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Data source: USGS documentation.