Richter Scale Facts for Kids

What are earthquakes? Earthquake is said to happen when on the earth's surface there is shaking, rolling or sudden shock. They happen along the 'fault lines' on the crust of the earth. Often they can be felt over large landmass, but they do not last more than a few seconds. Although it is said, animals are able to feel that there is going to be an earthquake, it cannot be predicted. However, scientists are working towards being able to predict earthquakes. Even if the earthquakes cannot be predicted, their intensity is easy to measure, thanks to an instrument called 'Richter Scale'. Here is a brief about this instrument, and the various facts associated.

Richter Scale Explained

The Richter scale was developed by Charles Richter of the California Institute of Technology in 1935. It is also known as Richter magnitude scale. It is used to measure the intensity of the earthquake. A single number is assigned to quantify the amount of seismic energy released by an earthquake. This assignment is made after calculations using information gathered by a seismograph.

The magnitude is a base-10 logarithmic scale. In other words, when there is a whole number jump, it indicates a ten-fold increase in the magnitude of the earthquake. Therefore, an earthquake with 6 on the Richter scale is 10 times greater than an earthquake with 5 on the same. Therefore, the increase in intensity between an earthquake of 5 and 7 on the Richter scale is 100 times. Let us look at a few facts about earthquakes and their numbers on the Richter scale. For kids, this might prove to be useful in gauging the strength and fury of an earthquake.

Interesting Facts

The largest earthquake ever recorded on a Richter scale is 9.5. Although there have been earthquakes, which were far more stronger in intensity than this earthquake. Majority of the earthquakes, which have been recorded till date have been less than 3 on the scale. They are actually tremors, that are not felt by humans and are known as microquakes. The earthquakes, that cause damage are more than 4 on the Richter scale. A major earthquake is the one which registers more than 7 on the Richter scale.

Magnitude of Earthquake on Richter Scale	Description of the Earthquake	Effects of the Earthquakes	Occurrence Frequency
Less than 2.0	Micro	The earthquake is not felt	Approximately, 8000 per day
2.0 to 2.9	Minor	Normally not felt, but recorded	Approximately 1000 per day
3.0 to 3.9	Minor	Normally felt, but rarely are any damages caused	Approximately 49,000 per year
4.0 to 4.9	Light	Often felt indoor, with shaking of indoor items and rattling noises. Significant damage is not caused	Approximately 6200 per year
5.0 to 5.9	Moderate	Major damage can be caused to poorly constructed buildings and little damage to well constructed buildings	Approximately 800 per year
6.0 to 6.9	Strong	It can be very destructive in areas as far as 160 kilometers from the epicenter in populated areas	Approximately 120 per year
7.0 to 7.9	Major	It is known to cause severe damage over larger areas	Approximately 18 per year
8.0 to 8.9	Great	It can cause severe damage in several hundred miles across	Approximately 1 per year
9.0 to 9.9	Great	Devastating in areas for several thousands of miles	Approximately 1 per 20 years
10.0 +	Epic	Has never been recorded	Extremely low and cannot be estimated

One of the most important points to remember in this table is that the effects of earthquakes, mentioned in the table, are for shallow earthquake in a populated area. Although the biggest earthquake ever recorded and other larger earthquakes, do have a large magnitude on the Richter scale. However, they do not necessarily cause intense surface effects. There are other factors which also have a role to play for example, local surface and subsurface geologic conditions, etc. To explain this better, if a particular area has unstable ground, such as sand or clay, it is very likely to experience more noticeable effects in comparison to an area at an equal distance from the earthquake's epicenter, but which has firm ground, like granite, marble, etc.