Understanding Earthquakes to Better Prepare for Adversities

understanding earthquakes

Understanding Earthquakes to Better Prepare for Adversities

On January 9th, 2018,  a powerful earthquake was felt across Central American countries. Triggered approximately 125.4 miles northeast of Honduras coast, the 7.6 magnitude earthquake was felt across the Caribbean countries. Reports indicate that this is by far the strongest earthquake to hit the region.

Immediately after the earthquake struck, tsunami alarms were issued. An hour after the quake, it was clear that these warnings were false. Officials in nations such as the Cayman Islands, Puerto Rico, Cuba and other central American countries prone to earthquakes, were expecting huge waves to rock the coasts of several Central American countries, but this hasn’t happened.

Considering that the earthquake had a 7.6 magnitude, it comes as a surprise to many individuals that the tsunami alert turned out to be false. What people seem to forget is that Tuesday’s earthquake is nowhere close to the 8.9 magnitude earthquake responsible for triggering a 30-foot-high tsunami in Japan back in 2011.

The big question is, why did the tsunami alert turn out to be wrong? Or why was there the formation of a tsunami? To answer this, there needs to be an understanding of the factors that come into play before the creation of a tsunami, the most significant being magnitude.

Earthquake Magnitudes Rating

Earthquake magnitudes are measured using a logarithmic scale. Each whole value on the scale represents an earthquake ten times stronger than the previous whole number. What this means is that an earthquake with a magnitude rating of 5 is ten times stronger than that of an earthquake having a magnitude rating of 4.

After understanding the how the magnitude rating works, it comes as no surprise that there is a staggering difference between an earthquake with a magnitude rating of 7.6 and one with a magnitude rating of 8.9. For an earthquake to trigger a tsunami, it should at least have a minimum rating of 6. Tsunami warnings are issued when earthquakes with ratings in their higher 7s hit. Earthquakes that have a rating of 7.5 or below at times create seismic waves which can have adverse effects on a coast or individuals residing near or on the beach.

Correlation Between Fault Lines and Tsunamis

An earthquake will lead to a tsunami if its seismic movement shits the position of land situated on a fault line upwards or downwards. This means that during an earthquake, the resulting vertical displacement of the sea floor is responsible for creating a tsunami. As the sea floor moves up or down, water is displaced hence moving in all directions. As the displaced water moves outwards, it accumulates into big waves causing tsunamis. On the other hand, an earthquake that shifts the land’s position horizontally can hardly result in a tsunami. The energy of horizontal earthquakes does not displace the water columns in the ocean.

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