KUMAMOTO: A security camera captured the moment a huge crack appeared in a rice paddy in Yatsushiro, Kumamoto prefecture, when the massive Kumamoto earthquake struck on July 28.
Yatsushiro is located more than 10km from the epicentre of the 2026 Kumamoto earthquake, which registered the maximum 7 on the Japanese seismic intensity scale.
“This is extremely rare and very useful for understanding the mechanism of earthquakes,” said an expert who viewed the footage.
The footage was captured at about 4.27pm on the day of the quake by a security camera installed at a store near the rice paddy in Yatsushiro, where the quake registered an upper 6. The video shows the ground shifting, exposing a fault line.
From security footage
The store’s owner, Mitsuaki Matsumura, 45, said: “I was in a meeting inside the store when I felt the shaking. I’ve never experienced one so strong before. We evacuated to the parking lot, and when I looked toward the rice paddy about 50m away, I saw the huge crack. The ground was uneven, and I could see a brown layer of earth.”
The crack is about 20m long, and the ground on one side is now about 1m higher than the other. Part of the concrete pavement of the road on the south side also lifted off the ground.
According to Tohoku University’s Professor Shinji Toda, a seismology expert who viewed the footage, these types of cracks, which are formed when the ground is uplifted due to seismic activity, are called fault scarps.
Toda noted that the location of the crack is near the direct extension of the Hinagu fault zone, which is believed to have triggered the earthquake, stretching from Mashiki, Kumamoto prefecture, to the Yatsushiro Sea.
Damage has also been confirmed in the surrounding areas, including the collapse of a shrine’s main gate and the vertical displacement of a bridge on the Minami-Kyushu Expressway.
“The fact that the fault scarp appeared a few seconds after the main seismic wave hit is because the speed of the fault slip is slower than the speed at which the shaking propagates from the focus,” Toda explained.
“Footage capturing the exact moment a fault scarp appears is extremely rare. This footage holds high academic value for studying the mechanisms of fault ruptures caused by earthquakes.” - The Japan News/ANN
