Emergency sirens and smartphone alarms jolted commuters across Japan on Friday afternoon with warnings of an impending magnitude 9.9 earthquake, though the ground ultimately remained still. The false alert, which triggered a rare emergency retraction by the Japan Meteorological Agency, disrupted public transit networks and sent sudden panic through urban centers before officials canceled the warning minutes later.
The automated alert system broadcast a forecast reaching up to shindo 7 on Japan’s seismic intensity scale, projecting severe shaking from Hokkaido to the Tokai region. In reality, a magnitude 6.9 earthquake had struck off Russia’s Kamchatka Peninsula at 12:38 p.m. on Friday, but the actual shaking registered in northern Japan peaked at a mere shindo 1.
Tokyo Streets and Transit Networks React to False Alarms
Pedestrians across Tokyo paused during lunch hours to check glowing mobile screens as disaster apps flashed countdown timers for a disaster that never materialized. Lola Milroy-Tompkins, a 20-year-old British student at Waseda University, recalled the sudden tension inside a campus cafeteria when the notifications sounded. I have never experienced an earthquake before and I expected the grand style shaking and everything to start falling around me,
Milroy-Tompkins said, noting that fellow students anxiously exchanged worried glances as they waited for tremors that failed to arrive.
Automated safety protocols also halted public transportation infrastructure across parts of the country. The Tokaido Shinkansen high-speed rail line temporarily shut down operations for 15 minutes as safety interlocks engaged before service resumed.
Meteorological Agency Investigates Calculation Flaws
Chief Cabinet Secretary Minoru Kihara stated during a Friday afternoon news conference that the government received no reports of damage related to the Kamchatka earthquake. However, Kihara acknowledged that the government took the disruption seriously due to the widespread anxiety, interrupted travel, and evacuation efforts prompted by the broadcast.
Ayataka Ebita, the head of the JMA’s earthquake and tsunami observation division, explained during a press briefing that the system mistakenly combined distant sensor data and applied a domestic magnitude formula to a tremor occurring far from Japan. Ebita confirmed that investigators ruled out any cyberattack and noted that sensor processing errors caused the severe overestimation, pointing out that 9.9 is the highest magnitude figure its systems can send out externally.
Previous Seismic Alert Malfunctions in Japan
According to the JMA, it was the first time an emergency earthquake warning had ever been withdrawn through a secondary cancellation broadcast.
The system has experienced notable malfunctions before. In July 2020, the agency issued an incorrect warning covering 15 prefectures, including Tokyo, after miscalculating a tremor’s location and magnitude. A similar technical failure occurred in August 2013, when background noise from a seabed seismometer merged with data from a minor earthquake, generating widespread false alarms across the Kinki region.
Frequently Asked Questions About the JMA Warning System
Why did the system broadcast a magnitude 9.9 earthquake?
The JMA stated that the automated system applied a calculation formula meant for domestic earthquakes to a tremor occurring far from Japan. The system also used different estimated quake locations to calculate the magnitude and predict shaking.
What is the historical context of earthquake magnitudes in the region?
The strongest earthquake in recorded history struck Biobio, Chile, in 1960 and reached a magnitude of 9.5.
Under what conditions does the agency issue a cancellation?
According to JMA policy, an official cancellation announcement is dispatched when the maximum observed seismic intensity is shindo 2 or lower, or when shaking is determined to have been caused by something other than an earthquake.