Japan earthquakes

M4.9 earthquake 122 km E of Yamada, Japan

A magnitude 4.9 earthquake struck 122 km E of Yamada, Japan on Fri, Aug 20, 1982, 8:38 PM JST (11:38 UTC), 41 km (26 mi) below the surface.

A larger quake followed: M5.4 165 km ENE of Miyako, Japan. This one was a foreshock.

Yamada forecast More in Japan

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The earthquake

Magnitude: 4.9 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Fri, Aug 20, 1982, 8:38 PM JST
UTC: 1982-08-20 11:38:03 UTC
Depth: 41.2 km (25.6 mi), shallow
Epicenter: 39.509° N, 143.376° E
Region: Japan
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
4.9	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · 21 stations
5.2	Mw, moment	ISCGEMSUP	Final · ±0.2

Did you feel it?

No one has reported feeling this quake to the USGS.

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.9 and up: 2 in the 60 days after this one and 14 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0001p5j (also filed as iscgemsup594085). Read Thu, Oct 1, 2026, 2:47 PM UTC.