M4.2 earthquake 31 km S of Koshima, Japan
A magnitude 4.2 earthquake struck 31 km S of Koshima, Japan on Fri, Mar 1, 1985, 8:14 AM JST (23:14 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M5.5 120 km NE of Naze, Japan. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 4.2 (mb), light
- Local time
- UTC
- 1985-02-28 23:14:08 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 29.956° N, 130.563° 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
- OPERATOR_ASSIGNED
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.5 and up: 1 in the 60 days after this one and 1 in the 30 days before it.
After
Before
Earthquakes todayJapan earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0002ca5. Read Wed, Sep 30, 2026, 1:52 AM UTC.