For centuries, Korea has been a quake-free zone, but recent events have caused that to change.



Of the 10 earthquakes in South Korea that registered 5.0 or higher on the Richter scale in its four decades of state measurement, half occurred after the 2011 Tohoku earthquake off the coast of Japan.



The record 9.1-magnitude undersea quake, a subsequent seismic sea wave or tsunami and aftershocks have claimed over 15,000 lives in Japan. However, it also had an impact on tectonic activities in countries across the strait, including Korea.



The quake, also known as the Great East Japan Earthquake, appears to have accelerated a stress build-up in faults on the Korean Peninsula and put forward a release of the accumulated energy associated with motions on active faults, causing earthquakes especially in southeastern part of the nation in recent years, said Kim Young-seog, a geology professor at Pukyong National University, in an interview with The Korea Herald.





Kim Young-seog, geology professor at Pukyong National University, gives a field lecture in a valley in South Gyeongsang Province. (Courtesy of Kim Young-seog)

But Korea still has no clue where the next target will be, or when it could happen again, he said, as the public sense of the nation being a quake-free zone has hindered development of geology and earthquake research.



A creation of a fault line map of the peninsula is crucial, to prevent the construction of buildings at or near zones with a high degree of an earthquake risk.



But the grand project, which will take at least 20 years to complete, only begun last year in the wake of Gyeongju earthquake.



“The government began to practically allocate a budget (for drawing a fault line map) after an earthquake hit Gyeongju, and that‘s when a discussion for a new project gained momentum,” Kim said. “However, it‘s too late to blame a certain entity for not trying 20-30 years ago.”



The void of the system invited confusion, especially in finding out the exact hypocenter of the quakes in Pohang.



The Korea Meteorological Administration was met with criticism after picking a fault line 7 kilometers away from the epicenter as the hypocenter. Academic circles have conceded that an unidentified active fault near Pohang caused the earthquake.



The confusion shed light on a 25-year project that Korea‘s Ministry of the Interior and Safety has embarked on, to secure locations of quake-prone fault lines since July 2017. Kim is currently a director of a team involved in the project, made up of 11 professors and 54 researchers from seven universities and two state-led institutions.



Backed by at most a 15 billion won ($13.9 million) budget, the team in the first five years plans to discover faults in North and South Gyeongsang Province, closest to Japan. The team will also make use of data gathered from Light Detection and Ranging, a remote sensing method to measure geographic features. In the next round of five years, the project will revolve around Seoul and the surrounding metropolitan area, according to a preliminary plan.



The process of identifying the active fault lines will be modeled after those of Japan and the United States, while the degree of activity will be graded following a guideline suggested by the government. Faults will be segmented according to the level of activity and designated a grade on the scale of 4. The fault, whose latest earthquake occurred in late Pleistocene era, or at most 126,000 years ago, will be considered active and will be given the grade of 1 or 2, according to the guideline.





Kim Young-seog