Relevant ministries and municipality estimated that the damage in the city could be worth more than 7.5 billion won ($6.8 million) after an on-site investigation. 

Gyeongju, which is some 370 kilometers southeast of Seoul, was struck by a 5.8 magnitude earthquake on Sept. 12. It was the strongest ever recorded by the Korea Meteorological Administration in the Korean Peninsula. 

A city is declared as a special disaster zone upon approval from the president when its public facilities are damaged due to large-scale natural disasters or accidents, and when municipalities are in need of financial support from the central government.

Gyeongju has already received 2.4 billion won from the Public Safety Ministry and 2 billion won from the Interior Ministry, respectively, in special subsidy taxes to restore damaged facilities

Aftershocks will continue to take place in the Korean Peninsula in the months to come, but there should be no more quakes stronger than 5.8 magnitude, the nation’s weather agency said.

A 3.5 magnitude earthquake struck the city on Wednesday morning, two days after a magnitude 4.5 quake shook the nation Monday night.

Among a total of 423 aftershocks recorded as of Thursday afternoon, most were assessed to be weaker than magnitude 3. Only two aftershocks recorded a magnitude of between 4 and 5, while 15 tremors have ranged from 3 to 4.

The Korea Meteorological Administration said that it has decided to install more than 100 additional seismic monitors nationwide to detect earthquakes within seven seconds of the disaster striking the county.

“It is very unlikely that a quake stronger than magnitude 6.5 will hit the nation again,” said Koh Yoon-hwa, the chief of the KMA, at a news briefing held to inform the public of the interim results of an analysis on the nation’s natural disaster warning system and what could have caused the series of earthquakes.

“It is possible to see aftershocks within the range of magnitude 3 to 4,” the KMA said. “It is difficult to predict when aftershocks will end and it is likely for them to last in the weeks and months to come.”

The KMA added that the epicenter of the foreshock in Gyeongju was 700 to 800 meters away from that of the main quake. “We found out that foreshocks, major quakes and aftershocks were seen as moving in the southwestern direction,” the agency said.

Nearly 90 percent of the aftershocks, including the powerful ones with a magnitude of 4 and over, took place within 2.5 kilometers from where the major 5.8 magnitude quake occurred, the KMA said. Almost 70 percent of the aftershocks took place within two days after the quake rattled the country, with the quakes hitting a depth of 15.2 kilometers on average.

“Currently, it takes 50 seconds to detect earthquakes stronger than magnitude 5 and notify relevant agencies and areas of the tremors, but we will reduce it to seven to 25 seconds,” said the KMA. “In order to do so, we will increase the number of seismic monitoring facilities from the current 206 to 314 by 2018.”

“Starting in November, the KMA will directly notify the public of the occurrence of natural disasters in association with the Cell Broadcasting System,” the agency said. “We believe we can measure the seismic activity within 10 seconds and notify the public within two minutes through text messages by 2017.”

The current system of sending alert messages to the public has been criticized for failing to inform them in time. The weather agency sends mobile alert messages in times of natural disasters after going through the Ministry of Public Safety and Security.

When the 3.5 magnitude aftershock jolted the country Wednesday, warning messages were sent to the public some 10 minutes after residents felt the shaking. On Monday night, the website of the Public Safety Ministry as well as the weather agency, which provide information on how to evacuate in case of quakes, also crashed due to heavy traffic.

The KMA also said that a team of eight relevant officials will be dispatched to Gyeongju to conduct an on-site investigation for six months from Sept. 20 to investigate the causes and impact of the series of quakes.

In response to the latest earthquakes, President Park Geun-hye ordered a comprehensive overhaul of the country’s national quake response system at a meeting with top aides at the presidential office on Thursday.

“It has been confirmed that the country had several problems in the process of responding to quakes because we have perceived our country as safe from such natural disasters,” she said.

“As it is possible that aftershocks (will) continue to take place, relevant ministries and officials should maintain readiness to more promptly and accurately promote public safety,” she said. 

Relevant ministries and state-run agencies are scrambling to assess, prevent and minimize the damage caused by quakes.

According to the Ministry of Strategy and Finance, it will revise relevant acts so that the special subsidy taxes of the Interior Ministry, the Education Ministry and the Public Safety Ministry can be used to reinforce public facilities to make them more earthquake-resistant.

The Ministry of Land, Infrastructure and Transport announced Thursday that it will inspect all major social infrastructure including bridges, tunnels and airports in the quake-stricken southeastern region.

Currently, 91.5 percent of major public facilities are designed to withstand quakes in the country, the ministry said.

A team of more than 420 officials from relevant state-run agencies will be put on the field to check the safety of some 5,300 public facilities in the region by the end of this year. It also aims to make express trains, expressways and bridges earthquake-resistant by 2018, ordinary trains by 2019 and intake towers by 2020.

The ministry announced plans Wednesday to revise construction codes to require all new structures that are two stories or above in height to be earthquake-proof.

The Korea Electric Power Corp. will also raise the level of safety of electric facilities in nuclear reactors and substations by enhancing their ability to endure quakes. 

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)