Difference between an Earthquake with intensity 7.1 and an earthquake with intensity 7.2

We all know what earthquakes are and what they can do. Recently, there have been many natural disasters in various parts of the world including Tsunamis, hurricanes etc. but earthquakes remain on top of the list with regards to the number of occurrences and the amount of damage they can do. Not all earthquakes are the same. Some are of such a low intensity that they can hardly be felt. You may feel as if you probably lost your balance for a second but it was actually a very short and harmless earthquake. Yet there are times when an earthquake can be so devastating that it can cause buildings to fall and people to die some of the worst deaths they can imagine. However, saying that one earthquake was of a greater intensity is just a vague comparison. Therefore we use a system of measuring the intensity of a particular earthquake. For that we need to know what causes an earthquake and how the intensity is measured. Also, we will see how a very small increase in the intensity magnitude can change the outcome of an earthquake.

An earthquake occurs due to sudden release of energy within the Earth’s crust which in turn, creates seismic waves. The seismism of a particular area is a measure of the frequency, size and types of earthquakes experienced in that area over time. To measure earthquakes we use seismometers. What is measured is called the moment magnitude. The scale used in called the Richter magnitude scale. An earthquake that has a measure of over 7 can cause serious damage in the surrounding areas based on the depth. It is more of a benchmark above which earthquakes can be labeled as very fatal.

Having understood this, it is easy to explain the difference between earthquakes of magnitude 7.1 and 7.2. As you may have inferred yourself, the basic difference is the magnitude and hence the effects. The latter, that is 7.2, is of a greater intensity. This is a measure of the logarithm of different waves whose amplitude is measured by seismometers. This difference may seem small, but mind you, it is huge and very damaging. Since we are using logarithm scales, the measure we get is actually a minimized version of the actual value. Moreover, a mere difference of 0.1 on the scale (the Richter scale) means that there is a 100% increase in the amplitude of the seismic waves we mentioned earlier. In other words, it denotes a 100% increase in the shaking that is experienced in an Earthquake.

In all waves and movements, a lot of energy changes are involved. When we move from the 7.1 intensity to the 7.2 intensity, we actually talk about an increase in energy by 3.1 times. This means that an earthquake of intensity 7.2 has 310% of the energy that a similar earthquake of intensity 7.1 would have! The 0.1 difference does not seem too small now does it?

When we say that the amplitude and the shaking has doubled and the energy is over three times what it was for every 0.1 unit increase in intensity, what we actually mean is that the damage caused has also at least doubled. Therefore an earthquake of intensity 7.2 will at least cause twice as much damage as an earthquake of intensity 7.1. On average, there might be twice as many collapsed buildings, twice as many people killed etc. provided that all other factors are kept constant.

Summary of differences expressed in points

1. Earthquakes’ intensity can be measured on the Richter scale; the higher the value, the greater the intensity of the earthquake, the lesser the value, the lower the intensity

2. An Earthquake of 7.1 is of a lower intensity of an Earthquake of 7.2

3. An Earthquake of 7.2 has 100% greater amplitude of seismic waves than an Earthquake of 7.1

4. An Earthquake of 7.2 has 100% greater shaking as an Earthquake of 7.1

5. An Earthquake of 7.2 has 3.1 times the energy of an Earthquake of 7.1

6. Due to greater amplitude, shaking and energy, an Earthquake of 7.2 is expected to cause at least twice the damage of an Earthquake of 7.1

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