How are earthquakes measured using the richter scale?
May 04, 2010
in
Earthquake Questions
As in, by the damage they do, or just how much they shake?
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One comment
Bearwithme on May 4, 2010 at 11:48 pm
The Richter scale grows by powers of 10. An increase of 1 point means the strength of a quake is 10 time greater than the level before it. Here’s how it works:
An earthquake registering 2.0 on the Richter scale is 10 times stronger than a quake registering 1.0. A quake registering 3.0 is 10 X 10 or 100 times stronger than a quake registering 1.0 A 4.0 is 10 X 10 X 10 or 1,000 times greater than 1.0 and so on.
The Richter Scale is used to rate the magnitude of an earthquake — the amount of energy it released. This is calculated using information gathered by a seismograph. The Richter Scale is logarithmic, meaning that whole-number jumps indicate a tenfold increase. In this case, the increase is in wave amplitude. That is, the wave amplitude in a level 6 earthquake is 10 times greater than in a level 5 earthquake, and the amplitude increases 100 times between a level 7 earthquake and a level 9 earthquake. The amount of energy released increases 31.7 times between whole number values.
Here are some examples:
9.0 — Causes complete devastation and large-scale loss of life.
8.0 — Very few buildings stay up. Bridges fall down. Underground pipes burst. Railroad rails bend. Large rocks move. Smaller objects are tossed into the air. Some objects are swallowed up by the earth.
7.0 — It is hard to keep your balance. The ground cracks. Roads shake. Weak buildings fall down. Other buildings are badly damaged.
6.0 — Pictures can fall off walls. Furniture moves. In some buildings, walls may crack.
5.0 — If you are in a car, it may rock. Glasses and dishes may rattle. Windows may break.
4.0 — Buildings shake a little. It feels like a truck is passing by your house.
3.0 — You may notice this quake if you are sitting still, or upstairs in a house. A hanging object, like a model airplane, may swing.
2.0 — Trees sway. Small ponds ripple. Doors swing slowly. But you can’t tell an earthquake is to blame.
1.0 — Earthquakes this small happen below ground. You can’t feel them.
See the sources below for additional information.