M4.5 Earthquake in the Izu Islands, Japan region

On October 14, 2025 at 23:29 UTC, a magnitude 4.5 deep-focus earthquake struck in the Izu Islands, Japan region, at a depth of 442.1 km and coordinates 30.3969°, 138.2382°. This earthquake was detected by 71 seismic stations with good location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — a useful intuition for the size of the slip patch on the fault.

This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 14 days ago in the Izu Islands, Japan region. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.

The epicenter is located in Japan, a region characterized by the intersection of four tectonic plates — Pacific, Philippine Sea, Eurasian, and North American — creating multiple subduction zones. The nearest mapped fault system is the Japan Trench. View all earthquakes in Japan.

Learn more: Magnitude scale · Aftershock sequences

Common Questions

How strong was the magnitude 4.5 earthquake in the Izu Islands, Japan region?

The magnitude 4.5 earthquake that struck in the Izu Islands, Japan region on October 14, 2025 at 23:29 UTC had a depth of 442.1 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 30.3969°, 138.2382°, which is in the Izu Islands, Japan region. View all earthquakes in Japan.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.

Is this the same earthquake as the M5.1 one earlier?

No. This magnitude 4.5 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier in the Izu Islands, Japan region. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Has Japan had earthquakes this big before?

The largest recorded earthquake in Japan was the M9.1 Tohoku earthquake of March 11, 2011. Today's magnitude 4.5 event is significantly smaller than that historical record.

What should I do after an earthquake?

If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.

M4.5 Earthquake in the Izu Islands, Japan region — October 14, 2025

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