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East Sea has experienced more than 30 earthquakes, large and small, since the end of last month.

Moreover, it is said that an earthquake like today's (15th) may cause a tsunami, but reporter Seo Dong-gyun took a closer look at what is happening under the sea and what we should prepare for accordingly.


This is the distribution of earthquakes that have occurred in East Sea since the end of last month.

Including today's 4.5 magnitude quake, the highest so far this year, there have been 2 earthquakes of magnitude 0.13 or higher in the region, and 36 smaller earthquakes combined.

Let's put these points on a East Sea fault map and compare them.

These are the perimeter of two well-known fault zones, the Hupo Fault and the Ulleung Fault, but they do not match exactly.

It means that there is new fault activity in between.

According to the fault map, this is where the reverse fault is located.

Today's earthquake is also consistent with the National Weather Service's analysis that it is a reverse fault movement.

This vertical movement of the ocean with transverse pressure, or narrowing force, can cause the fault to move up and down, causing a tsunami.

That's why tracking and monitoring of this earthquake is so important.

The East Sea was created 2500 million years ago, and although you may not realize it, it is now narrowing.

Because of this, it is assumed that this pressure activates this reverse fault movement.

[Lee Jin-han, professor of Earth and Environmental Sciences, Korea University: If you look at the GPS data, it closes at a rate of 1 cm per year. Reverse faults are created when they are subjected to compression movement, and they are rehabilitated into reverse faults using existing faults.]

The Japan Meteorological Agency said that a 1.6-magnitude earthquake in the area could cause a tsunami of up to 2 centimeters in East Sea.

[Kim Myung-so/Earthquake Analyst, Korea Meteorological Agency: Due to a reverse fault earthquake that moves up and down instead of left and right, there is a possibility of a tsunami if it occurs on a large scale on the seabed....]

It is a nuclear power plant designed to withstand a 20.7-magnitude and 0-meter tsunami, but it needs to be inspected as it is densely packed in the East Sea.

Another problem with earthquakes is that even if earthquakes have occurred frequently until today, it is difficult to predict what will happen tomorrow.

The earthquake site was the site of magnitude 10.1996 and 2019.4 earthquakes in 2 and 4, respectively.

Experts said that while a larger earthquake is unlikely, earthquake preparedness checks such as evacuation tips are urged as the magnitude of the quake is getting stronger.

(Video Editing: Kim Jin-won, CG: Jegal-chan, Lee Joon-ho)

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