M4.6 earthquake 4 km SSE of Chiba, Japan
A magnitude 4.6 earthquake struck 4 km SSE of Chiba, Japan on Wed, Aug 7, 1985, 10:32 AM JST (01:32 UTC), 76 km (47 mi) below the surface.
A larger quake followed: M5.9 2 km NE of Shiroi, Japan. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 4.6 (mb, body-wave), light
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1985-08-07 01:32:05 UTC
- Depth
- 75.6 km (47.0 mi), intermediate-depth
- Epicenter
- 35.562° N, 140.144° E
- Region
- Japan
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
What happened
The USGS’s account of the effects of this earthquake.
Felt (I JMA) at Ajiro, Tokyo, Yokohama and Utsunomiya.
From the USGS event page for usp0002hf4. U.S. Geological Survey text and figures are in the public domain.
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 1.6 and up: 8 in the 60 days after this one and 3 in the 30 days before it.
After
- 4.21 km WSW of Okegawa, Japan · 15032 days ago · 67 km deep · 73 km away
- 4.31 km SSE of Chigasaki, Japan · 15031 days ago · 125 km deep · 72 km away
- 4.211 km S of Y?ki, Japan · 15026 days ago · 60 km deep · 74 km away
- 4.26 km NW of ?hara, Japan · 15024 days ago · 66 km deep · 35 km away
- 4.44 km ESE of Shiroi, Japan · 15000 days ago · 83 km deep · 25 km away
- 4.25 km WNW of Ishige, Japan · 14996 days ago · 63 km deep · 67 km away
- 5.92 km NE of Shiroi, Japan · 14973 days ago · 85 km deep · 29 km away
- 4.36 km SSW of Ry?gasaki, Japan · 14973 days ago · 91 km deep · 32 km away
Before
Earthquakes todayJapan earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0002hf4. Read Fri, Oct 2, 2026, 11:32 PM UTC.