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Let's learn more about this earthquake with Seo Dong-gyun, a meteorological science team reporter.
Q. Was it before the Goesan earthquake in North Chungcheong Province, or did the investigation into the cause have begun?
[Reporter Dong-Gyun Seo: Yes, the fact that an earthquake occurred means that there is a 'fault' in the area where the crust is cut off.
The Korea Meteorological Administration said that there is no known fault in the area and that further investigation is needed.
Today (29th), as soon as an earthquake occurred, a domestic research team also carried a portable seismic device and headed to the site to investigate the fault.
First of all, it was determined that the earthquake was not caused by humans like the Pohang earthquake because the depth of the occurrence was about 12 km.]
Q. What is the result of seismic wave analysis that occurred in the middle of the inland?
[Reporter Dong-Gyun Seo: It is impossible to know what kind of fault there is in the area, but if you analyze seismic waves, you can know how the fault moved.
It was analyzed that the earthquake occurred in a horizontally moving fault where the crust shook up, down, left and right instead of up and down.
If you look closely at the fault line, you can see that there is a fault line from north-northeast to south-southwest.
It is similar to the fault lines around the area.
Faults like this occur even inland because the Philippine plate and the Pacific plate are pushed toward the Eurasian plate, which belongs to Korea.]
Q. The largest earthquake has passed, but should we prepare for aftershocks now?
[Reporter Seo Dong-gyun: That's right.
Now we have to prepare for aftershocks.
Aftershocks occur when the elastic energy around the fault is released after an earthquake.
Therefore, the magnitude and duration of the aftershock are proportional to the size of the main earthquake.
In the 2016 Gyeongju earthquake, a 4.5 magnitude aftershock occurred a week after the main earthquake occurred, and a 4.6 magnitude aftershock occurred three months after the Pohang earthquake.
Although this earthquake is smaller than Gyeongju and Pohang, earthquakes with a magnitude of 3.0 or greater can occur at any time, so you need to be thoroughly prepared.]
Q. Can you predict earthquakes in advance?
[Reporter Dong-Gyun Seo: Yes, mid- and long-term forecasts are currently possible.
In Japan and California, USA, the frequency and likelihood of earthquakes of a certain magnitude are forecast for decades to hundreds of years.
However, to do this, an active fault map must be prepared first.
Korea also started to produce this active fault map in 2017.
Fundamentally, the short-term forecast we need is impossible, so preemptive
earthquake-resistant design is needed first.]