A magnitude 6.1 earthquake struck the sea off Japan's eastern coast on Friday evening, shaking buildings in Tokyo and across the Kanto region. No tsunami warning was issued, and there were no immediate reports of damage or injuries, according to the Japan Meteorological Agency (JMA).
The tremor hit at 7:39 p.m. local time (10:39 UTC) in the waters off the Kanto region, the JMA said on its website. Its epicentre was in the North Pacific Ocean, roughly 145 to 170 kilometres off the coast east of Tokyo, depending on the agency measuring it. Shaking was felt in central Tokyo, and the quake registered intensity 3 on Japan's seven-point seismic scale in parts of Miyagi, Fukushima and Ibaraki prefectures.
What the agencies reported
The first figures were preliminary, and the agencies measuring the quake did not agree on every detail — which is normal in the first hours after a seismic event, as different sensor networks refine their readings.
| Detail | Japan Meteorological Agency | US Geological Survey | India's National Centre for Seismology |
|---|---|---|---|
| Magnitude | 6.1 (preliminary) | 6.1 | 6.1 |
| Time | 7:39 p.m. JST | 10:39 UTC | 4:09:29 p.m. IST |
| Depth | About 10 km | 29 km (reviewed solution) | 40 km |
| Epicentre | 35.0°N, 142.2°E | About 169 km south-east of Asahi; 144 km south-east of Hasaki | 35.087°N, 142.254°E |
All three agencies agreed on the magnitude — 6.1 — and on the broad location: the sea off the Kanto coast, east of Tokyo. The depth estimates differed, from about 10 km in the JMA's preliminary reading to 29 km in the USGS's reviewed solution and 40 km in India's National Centre for Seismology reading. The USGS said its solution had been reviewed by a seismologist and that its figures had been revised several times since the first report.
Why the numbers differ: seismologists locate an earthquake by combining arrival times from sensors around the world. Early estimates use the fastest available data; as more stations report in, the location and depth are refined. A shallow offshore quake is also harder to pin down precisely than one under land, because there are no sensors in the sea above the epicentre. The magnitude — the figure that matters most for how much energy was released — was consistent across all three agencies.
No tsunami warning — but a forecast was issued
No tsunami warning was issued after the quake, Japanese authorities said. The JMA did, however, issue a tsunami forecast for the eastern Kanto coast, noting the possibility of slight sea-level changes. A forecast is a lower level of alert than a warning or advisory: it signals minor fluctuations rather than a dangerous wave.
The USGS issued a green alert for the event, indicating a low likelihood of casualties or damage, based on the quake's offshore location and magnitude.
Shaking felt in Tokyo
The quake was felt in central Tokyo, according to the JMA, and registered intensity 3 on Japan's seismic-intensity scale in parts of Miyagi, Fukushima and Ibaraki prefectures. On that scale, intensity 3 means shaking that nearly everyone indoors feels, with dishes on shelves rattling — noticeable, but well below the levels that damage buildings.
"Nearly all individuals indoors experience the tremor" and "dishes on shelves might rattle" — the Japan Meteorological Agency's description of seismic intensity 3, the level recorded in parts of Miyagi, Fukushima and Ibaraki.
There were no immediate reports of damage or injuries as of Friday evening, and no disruption to transport or power had been reported by the time the first assessments were published.
Why Japan watches offshore quakes closely
Japan sits at the junction of four major tectonic plates along the Pacific Ring of Fire, and the archipelago experiences around 1,500 earthquakes every year, most of them mild. Offshore quakes near the Kanto region draw particular attention because the region is home to Tokyo and tens of millions of people — and because the 2011 Tohoku earthquake, a magnitude 9.0 event off Japan's north-east coast, showed how a large offshore quake can generate a devastating tsunami.
Friday's quake was far smaller and much further offshore, and the absence of a tsunami warning reflected that assessment. But the JMA's tsunami forecast — and the fact that shaking reached the capital — explains why even a moderate offshore tremor is treated seriously in Japan.
What to watch next
Seismologists will continue refining the quake's location and depth, and the JMA will update its assessment if aftershocks follow. Offshore quakes of this size are often followed by smaller aftershocks in the same area, though most pass unnoticed on land. Any reports of damage, or a change in the tsunami forecast, would come first from the JMA and from local authorities in Chiba and Ibaraki prefectures.
Frequently asked questions
Was there a tsunami warning?
No. No tsunami warning or advisory was issued. The JMA issued a tsunami forecast noting possible slight sea-level changes along the eastern Kanto coast — a lower-level notice that does not indicate a dangerous wave.
How strong was the shaking in Tokyo?
Shaking was felt in central Tokyo, and the quake measured intensity 3 on Japan's 0-to-7 seismic-intensity scale in parts of Miyagi, Fukushima and Ibaraki prefectures. Intensity 3 is felt by nearly everyone indoors but does not damage buildings.
Why do the agencies give different depths?
Depth is the hardest figure to pin down quickly, especially for an offshore quake with no sensors above the epicentre. The JMA's preliminary estimate was about 10 km, the USGS's reviewed solution put it at 29 km, and India's National Centre for Seismology reported 40 km. All three agreed on magnitude 6.1.
Was anyone hurt?
There were no immediate reports of damage or injuries as of Friday evening, and the USGS issued a green alert indicating a low likelihood of casualties or damage.
Key takeaways
- A magnitude 6.1 earthquake struck off Japan's Kanto coast at 7:39 p.m. local time on Friday, 6 November 2026.
- Shaking was felt in central Tokyo and measured intensity 3 in parts of Miyagi, Fukushima and Ibaraki prefectures.
- No tsunami warning was issued; the JMA issued only a forecast for slight sea-level changes.
- No damage or injuries were immediately reported, and the USGS issued a green alert for low casualty risk.
- Agencies differed on depth — 10 km (JMA), 29 km (USGS) and 40 km (NCS) — while agreeing on magnitude 6.1.
For now, the story is one of a significant tremor with a fortunate outcome: a magnitude 6.1 quake close enough to shake the capital, but far enough offshore — and with no tsunami — to pass without reported harm. The next updates to watch are the JMA's refined assessment and any aftershock reports from the Kanto coast.
