M4.6 earthquake 81 km NE of Kolonga, Tonga
A magnitude 4.6 earthquake struck 81 km NE of Kolonga, Tonga on Wed, Aug 21, 1985, 12:21 AM GMT+13 (11:21 UTC), 69 km (43 mi) below the surface.
A larger quake followed: M5.4 102 km ENE of ‘Ohonua, Tonga. 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), light
- Local time
- UTC
- 1985-08-20 11:21:26 UTC
- Depth
- 69.0 km (42.9 mi), shallow
- Epicenter
- 20.534° S, 174.612° W
- Region
- Tonga
- 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: 3 in the 60 days after this one and 2 in the 30 days before it.
After
- 5.4102 km ENE of ‘Ohonua, Tonga · 14970 days ago · 33 km deep · 69 km away
- 5.179 km ENE of ‘Ohonua, Tonga · 14959 days ago · 66 km deep · 73 km away
- 5.281 km ENE of ‘Ohonua, Tonga · 14959 days ago · 66 km deep · 77 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0002hy9. Read Wed, Sep 23, 2026, 2:20 PM UTC.