How is an Earthquake measured?

The power of an earthquake is expressed in terms of a magnitude on a scale called the Richter scale.

It is measured in Richter scale.

It is measured with the help of instrument called seismograph

If the power of an earthquake is more than 7 on the Richter scale, it is dangerous

Note

Richter scale is not linear

If 2 earthquakes measure 4 and 6 on the richter scale,it does not mean that second earthquake is 1.5 times first earthquake

It actually means that it is 1000 times the first earthquake

Seismograph

It is an equipment used to measure seismic waves of an earthquake

It has a vibrating rod or pendulum which is attached to a pen

During an earthquake,when earth vibrates,the pen records vibration on a piece of paper

Explanation

When earth vibrates, the vibrating rod of the seismograph starts vibrating.

The pen attached to the vibrating rod records the seismic waves on a paper which moves under it.

By studying these waves, scientists can construct a complete map of the earthquake.

They can also estimate its power to cause destruction.

The working of a seismograph can be seen in this video

How to Make buildings “Quake Safe”?

To make buildings earthquake safe, we should

• In Highly seismic areas,use mud and timber as building material inplace of cement
• Cupboards should be attached to walls so that they do not fall
• Wall clock,photo frames etc should be hanged where they do not fall on people in case of earthquake
• Hire Qualified Architects,Engineers for advice while making buildings
• Since some buildings may catch fire due to an earthquake, it is necessary that all buildings have fire fighting equipment in working order.

Questions

NCERT Question 6 - Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?

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