The 6.7 magnitude Manipur earthquake that jolted Bangladesh at the dawn is not that much severe in terms of intensity, shows the US Geological Survey (USGS) intensity data.
The severity of an earthquake can be expressed in terms of both intensity and magnitude. However, the two terms are quite different, and they are often confused.
According to the USGS, the intensity of the earthquake in Dhaka and Sylhet was V in Modified Mercalli scale.
The green circles are meant for level V and blue circles are meant for level IV intensity. Source: USGS
Chittagong, Mymensingh and Rajshahi experienced level IV intensity during the 6.7 earthquake. Dhaka also observed a level IV intensity.
Level IV and V intensity correspond with 4.0 to 4.9 magnitude earthquake.
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Intensity is based on the observed effects of ground shaking on people, buildings, and natural features. It varies from place to place within the disturbed region depending on the location of the observer with respect to the earthquake epicentre.
Level V intensity earthquake is felt by nearly everyone, many awakened. At this intensity some dishes and windows get broken, unstable objects overturns.
Source: USGS
Level IV intensity is felt indoors by many, outdoors by few during the day. Dishes, windows, doors gets disturbed; walls make cracking sound. In this level of intensity, sensation like heavy truck striking building is also felt.
The intensity is a number (written as a Roman numeral) describing the severity of an earthquake in terms of its effects on the earth's surface and on humans and their structures. The Modified Mercalli scale is one of the most commonly used scale in the United States.
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There are many intensities for an earthquake, depending on where you are, unlike the magnitude, which is one number for each earthquake.
The magnitude is a number that characterizes the relative size of an earthquake. Magnitude is based on measurement of the maximum motion recorded by a seismograph.
