Question

The Mercalli scale grades the earthquake on ____________.
A. 10-point scale
B. 12-point scale
C. 15-point scale
D. 20-point scale

Answer 1

Hint: In general terms, trembling of the earth’s crust because of the displacement of rock strata in the interior of the earth is termed as earthquakes. The average occurrence of earthquakes excluding those occurring on the ocean floor is one every year.

Complete answer: Earthquakes come into existence due to the sudden displacement of earth’s rock strata along the lines of weakness. The sudden displacement of rocks strata causes vibration in the earth’s crust. Owing to vibrations, rocks break and particles next to the break are set in motion. Thus, one rock mass moves against another and these movements cause vibrations. Some of these vibrations reach the surface of the earth and are known as Earthquakes. If the rock break occurs very much deep in the earth’s interior the vibration does not reach the surface and earthquakes are not experienced.

Earthquake shocks are measured on the basis of magnitude and intensity. The scale which is used to measure the magnitude is termed as the Richter scale. The energy released during the earthquake is referred to as Magnitude. It is expressed in an absolute number of 0 to 10. On the other hand, the intensity scale measures the damage caused by the earthquake and is named after Mercelli, an Italian seismologist, thus the name Mercalli scale. This scale grades the earthquake on a 1-12 point scale.

Thus, the correct answer is option (B).

Note: The science that studies earthquakes is known as Seismology. The term Seismology has been derived from the Greek word ‘Seismos’ which means earthquake. The Mercalli scale has its own disadvantages, its strength is not appropriate and is considered less scientific. The reason is that it depends on visual observation accounts of loss and destruction.