Earthquake Magnitude vs. Intensity

Difference Between Earthquake Magnitude and Intensity

The two dimensions of an earthquake are its Extent and intensity. The earthquake is of natural disasters that occurring in various parts of Earth, causing great devastation and loss of property and lives. This earthquake is a result of movement of tectonic plates beneath the crust of the earth. Because the movement of these plates, by meandering or turning of the earth that causes a turmoil, which is estimated in the form of wavering. The earthquake is unpredictable and occurs without any warning. The study by seismologists of their frequency of occurrence at different locations and calculates the chances of them occurring in the future. The extent and intensity are two characteristics of the earthquake that enlighten a lot about them. Many people are often perplexed about the difference between the two. This article intends to find the difference between the extent and intensity of an earthquake so that people can have a better understanding of earthquake. A seismologist, speaking of the earthquake,   makes use of the magnitude and intensity quite often as it makes sense to understand that they mean by these words.

Magnitude of Earthquake

The magnitude of an earthquake is a value that tells an onlooker the amount of seismic energy released by this. It is a single value and does not depend on the distance from the epicenter. It is calculated by measuring the magnitude of the seismic influence (for a Seismometer). The scale that is used to the measure extent of an earthquake Richter scale range. It is a logarithmic scale division and allocates the values ​​of 1-10 to the extent of any earthquake. Hence, it is apparent that on the Richter scale, the power of devastation of an earthquake is in direct proportion with the value allocated. As divisions in logarithmic, an earthquake of magnitude 5.0 has value ten times greater shaking an earthquake measuring 4.0 on the scale. The extent of Richter scale has now given way to wide range of time that produces similar results but more accurate than the Richter scale.


The intensity of an earthquake is the property that indicates the effects and damage caused by this. Obviously the intensity varies as we go further from the epicenter of the earthquake. It can be determined by taking stock of the devastation in areas affected by the earthquake. The scale used to describe the intensity of earthquake is termed as Mercalli, as it was developed in 1902 by Giuseppe Mercalli. Today the modernized versions of this scale is used anywhere to talk about the intensity of the earthquake at given place.

How is Intensity different from Earthquake magnitude?

Thus it is clear that the scope is a fixed value independent of distance from the epicenter, while the intensity is a varying value that is different in different places depending on its distance from the epicenter. The intensity decreases as we move further away from the epicenter. The act of allocating an intensity value depends on the perception of local people and their responses are taken into account estimated when the intensity is calculated. On the other hand, the Magnitude is an autonomous value which measures the seismic energy released and is always fixed.

Recently, in 2011, Japan and New Zealand experienced earthquakes. On Richter scale, it measured 8.9 in Japan and 6.3 in New Zealand. But the intensity of the earthquake was extra in New Zealand and Japan. This is because the Japanese earthquake was centered in the Pacific Ocean 80 miles away from the Japanese city nearest Sendai as the epicenter of New Zealand was only six miles from the center of Christchurch that was completely destroyed due to the earthquake. The devastation in Sendai was caused by the subsequent Tsunami that was created by the massive earthquake.


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