The largest earthquake ever recorded was a 9.5 magnitude earthquake in Valdivia, Chile on May 22, 1960. The tremors lasted for 10 minutes and went down in history as the Great Chile Earthquake.
According to the US Geological Survey (USGS), the tremors were so strong that one man who survived the earthquake thought he was under nuclear attack because of the Cold War.
But is it possible for an earthquake larger than 9.5 to occur on Earth? Scientists say the answer is “yes”, but the chances of such an event are very low.
For an earthquake larger than 9.5 magnitude to occur, a huge piece of the Earth’s crust would have to break, meaning a fault would have to move both very deep and very long. There are not many places on Earth where this could happen, geologist Wendy Bohon told Live Science.
Bohon said that a magnitude 9.5 earthquake is about the upper limit of what our planet can produce, and that a magnitude 10 earthquake seems extremely unlikely.
The USGS also states that there is no known fault on Earth that could produce a magnitude 10 earthquake and that if there were such a fault, it would have to wrap almost the entire planet.
Magnitude is a concept used to measure the energy released in an earthquake. The concept of “intensity”, which is used to describe the impact of an earthquake, is different from magnitude. Magnitude also does not indicate how strongly people feel the shaking.
Scientists say that regardless of the magnitude, the intensity of an earthquake will vary depending on the proximity to the epicenter and the ground they are on.
Different scales can be used to measure the magnitude of an earthquake. For example, the magnitude of the first of the devastating earthquakes centered in Kahramanmaraş and affecting 10 provinces yesterday (February 6) was announced as 7.4 by Kandilli Observatory and 7.7 by USGS.
The reason for this was that Kandilli Observatory initially announced the magnitude of the earthquake according to the Richter Scale, while the USGS used the moment magnitude (Mw) scale. Kandilli Observatory then updated the magnitude of the earthquake to 7.7 Mw to correct the confusion.
Between 7.4 and 7.7 may seem close in numerical terms, but as earthquakes get bigger, each digit after the comma in the measurement can reflect a huge difference because the scale increases logarithmically, that is, exponentially, rather than linearly. Bohon explained the exponential increase in earthquake magnitude with the example of spaghetti:
[su_quote]If breaking a strand of spaghetti is equivalent to a magnitude 5 earthquake, it would take 32 strands of spaghetti to release the energy of a magnitude 6 earthquake. On this spaghetti scale, 1024 strands need to break for a magnitude 7 earthquake and 32,768 strands need to break for a magnitude 8 earthquake.[/su_quote]
As can be seen in this example, the energy difference between magnitude 7 and 8 earthquakes is much greater than the difference between magnitude 5 and 6 earthquakes. Therefore, there is a huge difference between announcing a 5.5 earthquake as 5.6 and announcing a 7.4 earthquake as 7.7.