Shallow M5.6 earthquake hits offshore northern Honshu, Japan

A shallow M5.6 earthquake was detected at 18:44 UTC on April 21, 2026, about 140 km (87 miles) east of Noda, Japan. The event was recorded at a depth of 35.0 km (21.7 miles), based on data provided by the US Geological Survey (USGS).

The earthquake’s epicenter was located at 40.2°N, 143.5°E in the Pacific Ocean, offshore northern Honshu. This region is prone to seismic activity due to its position along the boundary between the Pacific Plate and the North American Plate, east of the Tohoku coast.

Given the offshore location, there are likely maritime routes, fishing areas, and regional shipping lanes in the vicinity. Critical infrastructure in northern Honshu, such as ports and coastal transportation networks, may be several dozen kilometers to the west but were unlikely to be directly affected given the quake’s distance from the mainland.

There is no tsunami threat associated with this earthquake, based on its location and available data.

The significance index is 482 (on a scale that runs through 1 000), based on magnitude, felt reports, and estimated impact.

Japan is part of the seismically active Pacific ‘Ring of Fire,’ where the Pacific Plate subducts beneath the North American Plate, resulting in frequent moderate to strong offshore earthquakes along the Tohoku region.

This information was last updated at 19:04 UTC on April 21, 2026.