Some parts of Seoul's main metro lines including the part connecting Myeongdong Station and Sookmyung Women's University on Line No. 4 have still not completed earthquake-proofing work after failing a test six years ago.
Line No. 4 is being used by 1.2 million people each day.
According to data from the Korea Infrastructure Safety and Technology Corporation submitted to Saenuri Party lawmaker Chung Woo-taik, the section on the Line No. 4 connecting Myeongdong, Hoehyeon, Seoul Station, and Sookmyung Women's University stations failed to pass earthquake resistance tests in 2007 and 2008.
But despite warnings that it could collapse in the event of an earthquake, no reinforcement work has taken place, Chung said.
Currently, buildings in Korea need to be resistant against earthquakes of 5.5 to 6.5 on the Richter scale, depending on the nature of the building. Chung said, "Earthquakes on the scale of 5 to 5.9 can cause serious damage to a building, and earthquakes of 6 to 6.9 can destroy it."
Out of 191 major buildings nationwide under the management of the KISTEC, 100 are at the risk of destruction in the event of an earthquake, he added.