USGS Confirms M4.6 Earthquake in Japan

A seismic event measuring magnitude 4.6 has been recorded by global monitoring networks, with the epicentre located 219 km SSE of Wada, Japan. The earthquake occurred at 12:17 UTC on Sunday, September 6, 2026 and was detected at a focal depth of 35.0 km.

Seismological Overview

Earthquakes are the result of sudden energy release in Earth's crust, most commonly along fault lines where tectonic plates interact. This energy radiates outward as seismic waves — measured and characterised by networks of seismographs operated by agencies including the USGS, JMA, EMSC, and GFZ.

Japan sits at the convergence of the Pacific, Philippine Sea, Eurasian, and North American tectonic plates, making it one of the most seismically active countries on Earth.

Event Parameters in Detail

Magnitude: 4.6 (moment magnitude scale, Mw) — a moderate earthquake.
Depth: 35.0 km
Location: 219 km SSE of Wada, Japan
Time: 12:17 UTC on Sunday, September 6, 2026

At a focal depth of 35.0 km, this is classified as a shallow earthquake (0–70 km). Shallow events are typically the most damaging: the seismic energy has less distance to travel before reaching the surface, resulting in stronger and more abrupt ground shaking at the epicentre.

Energy and Ground Motion

A magnitude 4.6 earthquake releases approximately roughly 500 tonnes of TNT of energy. For comparison, this exceeds the energy released by most conventional explosive events and is sufficient to shift tectonic stress in measurable ways across a wide region.

Moderate earthquakes are felt by virtually everyone near the epicentre. Strong shaking lasting 10–30 seconds can topple unsecured items, crack plaster, and cause poorly anchored objects to fall. Aftershocks are common following moderate events.

Significant damage can occur to vulnerable structures — particularly unreinforced masonry, old adobe buildings, and poorly maintained older construction. Well-engineered modern buildings are designed to withstand this level of shaking with minimal structural impact, though contents may shift and non-structural elements (ceilings, partitions) can be damaged.

Regional Seismic History

Japan experiences roughly 1,500 earthquakes per year that are strong enough to be felt. The country has developed one of the world's most sophisticated earthquake early-warning networks, capable of alerting millions of citizens within seconds of a major rupture.

Public Safety Guidance

For residents in the affected area, the immediate priority is assessing personal safety and structural integrity. Fasten heavy furniture — bookshelves, water heaters, cabinets — to walls using earthquake straps. Store breakable items on lower shelves and heavy items closest to the floor. These simple steps significantly reduce the risk of injury from falling objects.

Keep an earthquake emergency kit accessible at home. It should include at least 72 hours of water (4 litres per person per day), non-perishable food, a first aid kit, torch, battery-powered radio, copies of important documents, and essential medications. Reviewing and restocking this kit annually is strongly recommended.

If you are in Japan, follow J-Alert instructions and refer to local municipal evacuation maps. Many buildings constructed after the 1981 revised building code are designed to withstand strong shaking.

Continued Monitoring

The USGS and regional seismic networks will continue to monitor this event for aftershock activity. QuakeWatch aggregates this global data in real time — you can view all current seismic activity on our live map, or explore our earthquake science guides to learn more about the forces behind events like this one.

How QuakeWatch Tracks This Event

QuakeWatch sources earthquake data directly from the USGS ComCat (Comprehensive Catalog), which aggregates data contributed by seismic networks worldwide including JMA (Japan), EMSC (Europe and Mediterranean), GFZ (Germany and global), Geoscience Australia, and dozens of national and regional networks. This data is refreshed every 60 seconds, ensuring that new earthquakes appear on our live map within minutes of being processed by the USGS. You can also submit a felt report for this earthquake directly on its detail page.