In the aftermath of the Gangwon earthquake… Experts “Possibility of a stronger earthquake” :: sympathetic media Newsis news agency ::

Analysis of local fault zone weakening by ‘cluster earthquake’

It is difficult to determine the foreshadowing of a major earthquake… there is a possibility

Experts Emphasize ‘Steady Fault Monitoring’

[서울=뉴시스]Reporter Hong Yeon-woo = A 4.5-magnitude earthquake occurred in the northeastern sea of ​​Donghae-si, Gangwon-do on the 15th, and as large and small earthquakes follow one after another in the nearby area, concerns are growing that a larger earthquake may occur. Experts said that the possibility cannot be ruled out, and emphasized the need for steady fault monitoring.

According to the Korea Meteorological Administration, an earthquake of magnitude 4.5 occurred at 6:27:37 am on the same day in the sea area 52 km northeast of Donghae City, Gangwon Province. This is the largest earthquake in the Korean Peninsula this year. It is the 22nd earthquake in history on the Korean Peninsula and the 20th among earthquakes in South Korea.

Experts defined earthquakes that occurred recently in Donghae, Gangwon Province, including the earthquake that occurred today, as ‘cluster earthquakes’ that occur frequently in a small area, and analyzed that fault zones have weakened because of this.

A total of 13 earthquakes with a magnitude of 2.0 or higher occurred in the waters of Donghae City (based on the radius of the epicenter of the earthquake on this day within 5 km) for about 3 weeks since the 23rd of last month. If earthquakes with a magnitude of 2.0 or less are included, the number of earthquakes in three weeks increases to a total of 36.

Hong Tae-kyung, a professor of earth system science at Yonsei University, said, “In the case of this earthquake, earthquakes of magnitudes 3.5 and 3.1 occurred at the end of last month, followed by several small earthquakes in the form of clusters.”

Professor Hong explained, “The cause of cluster earthquakes is the accumulated stress on the fault plane. Cluster earthquakes are the process of relieving that stress, and (in the process of earthquake occurrence) the fault plane is weakened.” He added, “If the amount of stress remaining compared to the amount of stress released by a small earthquake is high, it can lead to a large earthquake.”

Experts believe that if cluster earthquakes continue in the East Sea region of Gangwon, the possibility of a major earthquake cannot be ruled out.

Professor Hong added, “Whether this earthquake will provide enough stress relief (of the fault) or whether it will develop into a larger earthquake due to the amount of remaining stress depends on the condition of the fault.”

Kim Yeong-sik, a professor at Pukyong National University’s Department of Earth Environment, said, “We still have to wait a little longer.”

However, Professor Kim predicted, “If (earthquakes) continue to occur, there is a possibility that a large earthquake will come.”

After all, they emphasized the need for constant monolayer monitoring.

Professor Hong said, “Monitoring the fault is important because it depends on the condition of the fault whether it will eventually develop into a larger earthquake or not.” He continued, “The sea area is a particularly difficult area to observe. The installation of an undersea seismometer is difficult in itself, and it is difficult without budget support.”

Professor Kim also said, “It is important to continue monitoring and prepare in advance for which areas will be at risk.”

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