Web posted
Saturday, March 4, 2000
Richter scale makes connection between quake's energy, damage
For centuries, earthquakes were one of the most feared and least understood phenomena in human existence.
Through the development of modern computing and science, using a scale Charles Richter developed in 1937, the magnitudes and effects of many earthquakes can now be recorded and studied with great reliability, according to Peter Haeussler, a geologist with the U.S. Geological Survey.
The Richter scale measures a consistent magnitude -- or force -- of energy released by earthquakes.
For each additional step up the Richter scale an earthquake's intensity increases by about 30 times, Haeussler said.
The Richter scale helps people understand the connection between magnitude and damage. Knowing how strong a quake has to be to cause destruction can help keep an earthquake in perspective.
What Richter magnitudes feel like:
Between three and four points, the quake will feel like the vibration of a nearby truck passing.
Between four and five points, the quake will cause small objects to upset and can awaken sleepers.
Between five and six points, the quake will make standing difficult and can damage masonry structures
Between six and seven points, the quake will most likely cause panic, and some structure walls may fall.
Between seven and eight points, the quake is likely to cause wholesale destruction, landslides, avalanches and large tsunamis.
Between eight and nine points, the quake will cause total damage, ground waves can be seen, cracks and rifts may appear on the ground, and land may uplift or sink. Alaska's Good Friday Earthquake of 1964 measured 9.2 on the Richter scale.
Information from"Earthquake Survival Manual" by Lael Morgan was used for this article.
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