Simulation Gives Dire Quake Outlook

What would happen if an earthquake similar to the one that hit Pyeongchang, Gangwon Province, on January 20 occurred in big cities such as Seoul, Busan, or Daegu?

It was confirmed on January 22 that there is a simulation available that can estimate damage from earthquake situations in Korea, and that the system has been producing results.

The earthquake and disaster response system which the government has been using since last August can estimate damage to buildings and casualties in case of earthquakes in specific areas based on basic data such as geological and building information. However, the simulation results have never been made public until now.

A civilian expert who has watched the system operate said, “The system has been run under the assumption that an earthquake registering 5.2 on the Richter scale took place 1.39 km northwest of Pyeongchang-dong, Jongno-gu, Seoul (latitude 37.62, longitude 126.96), 30km deep at 3:48 p.m.”

The outcome was shocking. In Seoul, Gyeonggi Province, and Incheon, 60,293 buildings were destroyed and 36,197 people died. In downtown Seoul alone, 52,530 buildings were destroyed and 27,640 citizens died.

This system has basic data on 6.5 million buildings and a population setting of 48,590,000. If the epicenter, time, latitude, longitude, and scale of a quake are entered, the number of victims and buildings damaged is sorted not only by cities and provinces, but also by smaller districts.

However, a government official says that this system, which has been developed at a cost of eight months and 1.1 billion won, needs to be more precise and that therefore, it is not an accurate estimate.

A civilian expert who participated in the system consultation said, “The simulation’s damage outcome for an earthquake in Pyeongchang is extremely exaggerated.” Jang Seung-pil, professor of the Department of Civil, Urban and Geosystem Engineering at Seoul National University (SNU), said, “In order to get a correct simulation outcome, precise data such as the distribution of houses and buildings, building vulnerability, and even fire department locations has to be input. However, that requires a huge amount of money and work.”

The center for seismic engineering at SNU and Seoul City produced results through a simulation in 1999. The research was on an expected damage situation on buildings within 1km² of Gangnam Station in the event of an earthquake with a magnitude of 6.3 on the Richter scale occurring near the Namhansanseong Fortress, 27.3km away from Gangnam Station.

The situation was based on the historic fact that an earthquake occurred on a similar scale near the Namhansanseong Fortress in A.D. 89. According to the simulation, 20-30 percent of low brick buildings were destroyed, but only 10 percent of apartment complexes were damaged. This research is valued as precise as it was done in a small area and a fact-finding survey was done on the buildings. The research excluded loss of life estimates.

An earthquake that could cause damage in reality is one that registers 5.0 or more on the Richter scale. The figure is the boundary between non-structural damage, such as cracks on walls and broken glass, to structural damage such as buildings falling down.

Jeong Gil-ho, a researcher at the National Emergency Management Agency, said, “An increase of 1.0 on the Richter scale leads to a 32-fold increase in earthquake power.” That means that an earthquake that registers 6.0 on the Richter scale has 32 times more destructive power than the one that registers 5.0.

Many experts point out that preparations for earthquakes in Korea are insufficient. Kim Jae-kwan, head of the center for seismic engineering, said, “We have no other option than praying for no earthquakes greater than 6.5 on the Richter scale.”

The government has mandated that buildings with more than six floors be earthquake-proof since 1988. In 1992, that mandate was extended to roads and bridges, and in 2005, buildings with more than three floors. However, the data of the Ministry of Construction and Transportation showed that 60 percent of buildings with more than six floors and more than 27 percent of main transportation facilities such as bridges and tunnels were not designed to be earthquake-proof.

Professor Kim said, “I cannot believe even earthquake-free buildings exist on paper,” referring to earthquake-proof standards that consider earthquake loads but which don’t have specific regulations on factors affecting building stability, such as reinforcing rods. He said, “We have to take this earthquake as an opportunity to check the ability to respond to earthquakes on the national level.” He advised, “The law on earthquake and disaster measures which is scheduled to be enacted in the first half of this year should include quantitative goals against earthquakes such as ‘if an earthquake with a magnitude of X occurs, we will minimize the damage by Y.”

kimkihy@donga.com