Experts Warn Of Earthquake Threat On Kego Fault Zone Anniversary

As Japan marks the 20th anniversary of the devastating Fukuoka Western Offshore Earthquake, experts warn of an imminent threat stemming from the Kego fault zone, urging residents to heighten their earthquake preparedness. On March 20, 2025, Fukuoka City commemorated this tragic date, which serves as a reminder of the seismic dangers facing the region.

To reinforce awareness, Fukuoka City has designated March 20 as ‘Citizens' Disaster Prevention Day.’ The city's Early Good District Citizens' Disaster Prevention Center organized events where participants could learn essential safety measures, such as participating in earthquake quizzes and experiencing simulated shaking akin to the 2005 earthquake’s intensity.

“It was a little scary,” commented a first-grade participant after experiencing a simulated earthquake action. Many participants shared their apprehensions about potential future disasters. One mother emphasized, “I want my child to learn ways to protect themselves because we never know when a disaster may strike.”

Experts highlight the significance of active fault research in understanding earthquake risks. Ms. Yuri Miyatake from a national research institute focuses her studies on the Kego fault, which has generated fresh insights since the last major quake in 2005. “In 2005, the Kego fault was believed only to exist on land, but further research revealed that an undersea segment triggered the earthquake,” Miyatake explained.

The investigation unveiled that the recent quake originated from an active fault on the northern side of the Kego fault zone, suggesting longstanding seismic activity. Experts estimate that the Kego fault zone may unleash another earthquake soon, considering its past seismic history. “The land segment of the Kego fault remained inactive during the 2005 quake; however, the stress redistribution from the underwater fault movement has heightened the likelihood of seismic events along the land fault,” Miyatake warned.

Seismic data suggests that quakes recur approximately every 4,000 years in this area, and it has nearly been that long since the last event, indicating a possible upcoming disaster. “The recent changes in stress due to the 2005 event have recalibrated the likelihood of a local quake,” affirmed Miyatake, raising alarm as new calculations emerge.

The threat associated with the Kego fault is concerning, particularly regarding the potential impact above the fault line. It is estimated that vertical shifts within the fault plane could lead to a grave collapse risk for buildings standing directly above. Furthermore, the ground conditions on the eastern side of the Kego fault exhibit weaknesses that may amplify tremors and make them longer lasting.

“In the event of a shallow quake, the shock may arrive quicker than earthquake warnings can be issued,” cautioned Kunihito Ito, a seismic tsunami prevention expert at the Fukuoka Meteorological Office. Ito highlighted the need for behavioral preparedness among residents, emphasizing that understanding what actions to take during such instances remains crucial.

Fukuoka Prefecture's projections regarding a potential earthquake from the Kego fault zone are stark. They anticipate a catastrophic scenario involving up to 1,183 deaths, 22,508 injuries, and the complete destruction of 17,967 buildings. The metropolitan area around the Kego fault is particularly vulnerable, as around 38,000 individuals in districts like Hakata and Tenjin could find themselves stranded and unable to navigate home following a major quake.

To safeguard residents, Fukuoka City has established 14 temporary shelters in the Tenjin area, including facilities at the city hall lobby and Tenjin Business Center. However, these facilities themselves may be compromised during an earthquake, prompting authorities to stress the importance of not rushing about and instead seeking safe locations nearby until official information is provided.

The realities of seismic hazards in Fukuoka remain, with numerous active faults assessed beyond the Kego fault zone posing risks of powerful tremors. It is unclear when a disaster may happen, underscoring the importance of consistent preparedness efforts. Families are reminded to bolster home safety measures, ensuring fixtures and belongings are secured, and to practice response strategies in various settings, such as at home, school, and workplaces.

Ultimately, as the Fukuoka community reflects on the past, it must also prepare for the uncertainties of the future—mindful of the seismic forces that could reshape their lives in an instant.