Tonga earthquakes

M4.8 earthquake 234 km SW of ‘Ohonua, Tonga

A magnitude 4.8 earthquake struck 234 km SW of ‘Ohonua, Tonga on Thu, Aug 4, 1977, 12:00 AM GMT+13 (11:00 UTC), 115 km (71 mi) below the surface.

A larger quake followed: M5.1 141 km SW of Vaini, 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
4.8 (mb), light
Local time
UTC
1977-08-03 11:00:25 UTC
Depth
115.0 km (71.5 mi), intermediate-depth
Epicenter
23.041° S, 176.299° 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.

Stations used
40

Nearest places

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

Nearby

Within 100 km, magnitude 1.8 and up: 4 in the 60 days after this one and 3 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0000pz0. Read Tue, Sep 22, 2026, 10:28 AM UTC.