(ORDO NEWS) — Very abnormal seismic activity worries scientists in South Korea, as this could be a sign of a large and very destructive earthquake.
Seismologists in South Korea are concerned about the unusual wave of earthquakes that have shaken the peninsula in recent weeks.
Some suggest that this sudden surge in seismic activity could be a harbinger of a large – and potentially very destructive – earthquake.
The Korean Peninsula is not traditionally considered part of the so-called Ring of Fire, seismically active fault lines that run along the edge of the Pacific Ocean.
However, seismologists are considering whether displacement of tectonic plates could become the new norm for Korea.
Last week, the Korean Meteorological Administration reported an aftershock of magnitude 2.8 in Wanju County, in the extreme southwest of South Korea. Despite the fact that no damage was recorded from a weak earthquake and no one was hurt, this is the first time since December 2014, when a tremor with a magnitude higher than 2 hit the region.
Two days before the Wanju earthquake in North Korea, an earthquake of magnitude 3.8 was discovered. The Southern Monitoring Agency quickly announced that it was a natural seismic activity to dispel any fears that it might be another underground nuclear test conducted by the regime in Pyongyang.
North Korea conducts its nuclear tests at its Punggye Ri test site, located in the north-east of the country, with the last explosion of a hydrogen bomb on September 3, 2017, which was recorded as an earthquake of magnitude 6.3.
Mysterious burst of seismic activity
But even more deep concern among experts was caused by more than 400 seismic shocks that occurred on April 26 in one area in the southern province of Cholla, in the extreme south-west of the peninsula.
The region has not reported seismic activity since the government first began collecting data in 1978.
Experts admit that they do not know for sure what causes activity, but there are some theories about why it grows up and down the peninsula.
“We are closely following events in South Choll because they are very unusual and occur in a very short period of time,” said Hong Tae-gen, professor of seismology at Yonsei University in Seoul.
“This is also unusual because they occur in a very small area and they are much deeper than usual,” he said.
Earthquakes on the peninsula usually occur at a depth of about 10 kilometers. These last tremors occur at a depth of 20 kilometers below the surface of the earth.
Explosion from the past
“We don’t know exactly why this is happening, but there are certainly some theories that need to be verified with further research,” Hong said. “My personal assumption is that what we are seeing now is the result of the Tohoku earthquake in Japan in March 2011.”
Also known as the Great East Japan Earthquake, the epicenter of the Tohoku earthquake struck 70 kilometers off the coast of northeast Japan at a depth of approximately 29 kilometers below the seabed.
It was the most powerful earthquake ever recorded in Japan, and the fourth largest in the world since 1900.
Powerful tsunami waves hit the shore, which devastated the Northern Japanese coast more than 40 meters high.
The waves hit the Fukushima nuclear power plant, releasing radiation and adding an extra layer to the crash. Nearly 19,000 people have died or are still reported missing.
Powerful earthquake ‘reoriented’ peninsula
“When the Tohoku earthquake struck, it moved the eastern part of the Korean Peninsula about 5 centimeters east,” said Hong.
“At the same time, she moved the western part of the peninsula about 2 centimeters east, which means that the earthquake stretched the crust of the peninsula by about 3 centimeters.”
According to Professor Hong, within a few months and years after the Tohoku tragedy on the Korean Peninsula, seismic activity was resumed, including 5.8 shocks in 2016, which was the largest ever recorded in Korea.
But the deeper tectonic activity of the plate was relatively calm until the beginning of this year.
Cause for concern
Yoshiaki Hisada, a professor of earthquake science at Kogakuin University in Japan, said historically there has been little significant seismic activity on the Korean peninsula, and the recent increase in earthquakes is a concern.
“Earthquakes can come and go in areas for a long period of time and can completely disappear for many years in some parts of the world, only to come back later,” he said.
“The earth consists of plates that always move, so stresses increase and decrease, but increasing the frequency of movements is something that needs to be carefully monitored. This is a warning sign.”
The Korean Meteorological Administration has set up a number of monitoring sites in South Cholla to collect seismic data and, in the worst case, issue warnings.
Professor Hong says that although there have not been any truly devastating earthquakes over the course of a century, historical records show that the peninsula is not completely immune from a massive tremor that could result in significant damage and loss of life.
“The literature that has survived from the Joseon Dynasty, which spans a little over 500 years until 1897, tells the story of earthquakes and damage to communities on the peninsula,” he said.
“From what the researchers can tell, it looks like they experienced earthquakes of magnitude 7, and if this happened in the past, of course, it is possible that something like this could happen again.”
“I would say that as a result of the Tohoku earthquake, there is an increased likelihood that Korea could experience serious tremors. We need to be vigilant.
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