The ground under the northern Ryukyu Islands did not stay still Thursday morning. At 04:04 UTC, a magnitude 6.1 earthquake hit 136 kilometres north-northeast of Hirara, Japan. The U.S. Geological Survey put the depth at just 10 kilometres.
Shallow. That is the kind that rattles nerves and buildings hardest.
No tsunami warning came. For the people of Hirara and the surrounding islands, that is a break. They know the double threat here.
The sea floor can lurch and then the water can rise. This time, only the earth moved.
The epicentre sat out in the ocean, far from the nearest town. That distance matters. A magnitude 6.1 is strong enough to crack walls and knock things off shelves.
But only if it hits close to where people live. The shaking that reached Hirara was weaker than what hit closer to the rupture point. Still, it was enough to wake people.
Enough to make them stop and brace. This part of Japan is seismically restless.
The USGS data shows that within roughly 300 kilometres of the epicentre, there have been at least 192 earthquakes of magnitude 5.0 or greater in the past 20 years. The strongest was a magnitude 7.0 earthquake in 2010. The ground here is never truly still.
For those on the islands, the shaking was the first signal. What comes next is the waiting.
Seismologists say aftershocks are common after a quake this size. They can last for days or even weeks. People in the affected area are advised to be prepared for further shaking.
That means sleeping lightly. Keeping emergency supplies close. Watching the ground beneath their feet.
The USGS detected the event through its real-time global seismic monitoring network. The agency tracks these events continuously.
But for the people living through this one, the data is abstract. What is real is the tremor that passed through their homes. The moment of silence after it stopped.
The question of whether another one is coming. A magnitude 6.1 is not the largest earthquake this region has seen.
But it is a reminder that the earth here is always moving. The people know that. They live with it.
They prepare for it. And when the shaking stops, they wait for the next one.
