Japan earthquakes

M4.6 earthquake 8 km ESE of Chiba, Japan

A magnitude 4.6 earthquake struck 8 km ESE of Chiba, Japan on Thu, Apr 30, 1981, 2:18 AM JST (17:18 UTC), 80 km (50 mi) below the surface.

A larger quake followed: M4.7 58 km SE of Katsuura, Japan. This one was a foreshock.

Chiba forecastMore in Japan

Map

Where this earthquake was located, with the others nearby. Select one for its page.

Open the live map with earthquakes

The earthquake

Magnitude
4.6 (mb), light
Local time
UTC
1981-04-29 17:18:49 UTC
Depth
79.7 km (49.5 mi), intermediate-depth
Epicenter
35.564° N, 140.203° E
Region
Japan
Tsunami flag
No
Status
Reviewed by a seismologist

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Depth from
FROM_LOCATION

Nearest places

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

Nearby

Within 100 km, magnitude 1.6 and up: 1 in the 60 days after this one and 3 in the 30 days before it.

After

  1. 4.758 km SE of Katsuura, Japan · 16573 days ago · 33 km deep · 100 km away

Before

  1. 4.342 km SE of Hasaki, Japan · 16595 days ago · 33 km deep · 92 km away
  2. 4.02 km N of Inashiki, Japan · 16602 days ago · 60 km deep · 47 km away
  3. 3.79 km NW of Ishige, Japan · 16604 days ago · 60 km deep · 73 km away

Earthquakes todayJapan earthquakesLive radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0001dew. Read Wed, Sep 30, 2026, 6:32 AM UTC.