EARTHQUAKEM4.7

M4.7 earthquake near Asahi, Japan

Map: the earthquake near Asahi, Japan, with plate boundaries

A magnitude 4.7 earthquake struck 6 km (4 mi) north of Asahi, Japan on Wednesday, October 28, 2026 at 18:32 UTC, at a depth of 42 km (26 mi), according to the U.S. Geological Survey. Shallow quakes like this one shake the surface hardest. The nearest city of a million or more people is Tokyo, about 82 km (51 mi) away.

MagnitudeM4.7
Depth42 km (26 mi)
Time (UTC)Oct 28 18:32
Location35.78°N 140.65°E
Nearest townAsahi · 6 km
Energy169 tons TNT
Aftershocks M2.5+1
Tsunami flagNo
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Why here?

This earthquake struck about 128 km (80 mi) from the boundary between the North American and Philippine Sea plates. Most earthquakes happen along plate boundaries like this one, where the pieces of Earth’s outer shell collide, pull apart or grind past each other. Stress builds up over years until the rock suddenly slips.

The red lines on the map are plate boundaries.

How strong was it?

Magnitude is logarithmic: each whole step releases about 32 times more energy. This magnitude 4.7 released roughly the energy of 169 tons of TNT. That is about 11 times the energy of a magnitude 4.0, a quake people nearby feel but that rarely causes damage. The strongest earthquake ever recorded, magnitude 9.5 in Chile in 1960, released about 16,000,000 times more than this one.

Aftershocks

In the first 4 hours after it, USGS recorded 1 smaller earthquake of magnitude 2.5 or more within 100 km (62 mi). It was a magnitude 4.3 on October 28 at 20:22 UTC.

Outside the United States, USGS mainly lists quakes of about magnitude 4 and up, so smaller aftershocks there are undercounted.

Earthquake history here

Before this earthquake, USGS had recorded 287 earthquakes of magnitude 6 or larger within 300 km (186 mi) since 1900. The strongest:

Official details, updates and the shaking map: USGS event page.

See every earthquake on October 28, 2026 or earthquakes by day.

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