Tonga earthquakes

M4.6 earthquake 235 km S of ‘Ohonua, Tonga

A magnitude 4.6 earthquake struck 235 km S of ‘Ohonua, Tonga on Mon, Apr 1, 1985, 4:45 AM GMT+13 (15:45 UTC), 33 km (21 mi) below the surface.

A larger quake followed: M5.0 299 km SSW of ‘Ohonua, Tonga. This one was a foreshock.

Nuku‘alofa forecastMore in Tonga

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

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The earthquake

Magnitude
4.6 (mb), light
Local time
UTC
1985-03-31 15:45:40 UTC
Depth
33.0 km (20.5 mi), shallow
Epicenter
23.447° S, 175.167° 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
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Nearest places

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

Nearby

Within 100 km, magnitude 1.6 and up: 2 in the 60 days after this one and 1 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0002dbe. Read Mon, Sep 21, 2026, 6:56 PM UTC.