M5.8 earthquake 16 km E of Iwanai, Japan
A magnitude 5.8 earthquake struck 16 km E of Iwanai, Japan on Sat, Aug 20, 1966, 6:32 PM JST (09:32 UTC), 159 km (99 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.8 (mw), moderate
- Local time
- UTC
- 1966-08-20 09:32:32 UTC
- Depth
- 159.4 km (99.0 mi), intermediate-depth
- Epicenter
- 42.981° N, 140.708° E
- Region
- Japan
- Strongest shaking
- IV, light shaking
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- IV, light shaking
- Peak ground acceleration
- 1.6% of gravity
- Peak ground velocity
- -0.2 cm/s
- Map
- Automatic
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Magnitude uncertainty
- ±0.54
- Depth from
- From location
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.5 and up: 0 in the 60 days after this one and 0 in the 30 days before it.
None recorded.
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event iscgem844732. Read Tue, Sep 22, 2026, 8:53 AM UTC.