Tonga earthquakes

M5.7 earthquake 108 km ESE of ‘Ohonua, Tonga

A magnitude 5.7 earthquake struck 108 km ESE of ‘Ohonua, Tonga on Thu, Mar 30, 1978, 11:00 AM GMT+13 (22:00 UTC), 33 km (21 mi) below the surface.

A larger quake followed: M5.8 59 km E of ‘Ohonua, Tonga. This one was a foreshock.

Nuku‘alofa forecast More in Tonga

Map

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

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The earthquake

Magnitude: 5.7 (Ms, surface-wave), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Mar 30, 1978, 11:00 AM GMT+13
UTC: 1978-03-29 22:00:26 UTC
Depth: 33.0 km (20.5 mi), shallow
Epicenter: 21.760° S, 174.011° W
Region: Tonga
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
5.7	Ms, surface-wave	USGS National Earthquake Information Center	Preferred · Reviewed
5.58	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.6	Mwc, centroid moment	Global CMT project	Preliminary

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: OPERATOR_ASSIGNED
Stations used: 133

Nearest places

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

Nuku‘alofa, TongaPopulation 22,400. Forecast141 kmESE

Nearby

Within 100 km, magnitude 2.7 and up: 8 in the 60 days after this one and 5 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0000tua (also filed as gcmtb032978c, gcmt19780329220026, iscgem685852). Read Fri, Oct 2, 2026, 1:09 PM UTC.