EARTHQUAKEM4.6

M4.6 earthquake near Iwaki, Japan

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

A magnitude 4.6 earthquake struck 124 km (77 mi) east-southeast of Iwaki, Japan on Thursday, October 8, 2026 at 04:41 UTC, at a depth of 46 km (28 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 Sendai, Japan, about 201 km (125 mi) away.

MagnitudeM4.6
Depth46 km (28 mi)
Time (UTC)Oct 8 04:41
Location36.75°N 142.23°E
Nearest townIwaki · 124 km
Energy120 tons TNT
Aftershocks M2.5+1
Tsunami flagNo
See it on the live 3D globe →Watch live on YouTube🔔 Get alerts near you

Why here?

This earthquake struck about 80 km (49 mi) from the boundary between the North American and Pacific 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 4.6 released roughly the energy of 120 tons of TNT. That is about 7.9 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 22,000,000 times more than this one.

Aftershocks

In the first 18 days after it, USGS recorded 1 smaller earthquake of magnitude 2.5 or more within 100 km (62 mi). It was a magnitude 4.4 on October 15 at 02:05 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 348 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 8, 2026 or earthquakes by day.

More from around the world