Tonga earthquakes

M5.4 earthquake 123 km NE of Hihifo, Tonga

A magnitude 5.4 earthquake struck 123 km NE of Hihifo, Tonga on Tue, Sep 8, 2020, 9:28 PM GMT+13 (08:28 UTC), 25 km (16 mi) below the surface.

A larger quake followed: M5.9 76 km NNE of Hihifo, Tonga. This one was a foreshock.

Apia 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: 5.4 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Tue, Sep 8, 2020, 9:28 PM GMT+13
UTC: 2020-09-08 08:28:53 UTC
Depth: 25.0 km (15.5 mi), shallow
Epicenter: 15.174° S, 172.980° W
Region: Tonga
Felt reports: 2
Strongest shaking: III, weak shaking
PAGER alert: Green
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
5.4	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.093 · 11 stations
5.53	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.2	Mwb, body-wave moment	USGS National Earthquake Information Center	Moment tensor · Reviewed

Shaking

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

Strongest estimated: III, weak shaking
Peak ground acceleration: 0.7% of gravity
Peak ground velocity: -0.7 cm/s
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

2 people reported to the USGS what they felt; the strongest reported shaking was III, weak shaking.

Estimated impact

The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.

Alert level: Green: little or no damage or loss of life expected

Deaths: estimated chance of each range
Range	Chance
Under 1	65%
1 to 10	30%
10 to 100	4%
100 to 1,000	Under 1%
1,000 to 10,000	Under 1%
10,000 to 100,000	Under 1%
100,000 to 10,000,000	Under 1%

Economic losses: estimated chance of each range
Range, million USD	Chance
Under 1	65%
1 to 10	30%
10 to 100	4%
100 to 1,000	Under 1%
1,000 to 10,000	Under 1%
10,000 to 100,000	Under 1%
100,000 to 10,000,000	Under 1%

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Strike-slip
Moment magnitude: 5.2 Mwb
Nodal plane 1: Strike 168°, dip 18°, rake 178°
Nodal plane 2: Strike 260°, dip 89°, rake 72°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 7.2 km horizontally, 1.8 km in depth
Magnitude uncertainty: ±0.09
Depth from: From modeling of broad-band P waveforms
Station coverage gap: 54°
Stations used: 163

Nearest places

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

Apia, SamoaPopulation 40,407. Forecast198 kmSW

Nearby

Within 100 km, magnitude 2.4 and up: 10 in the 60 days after this one and 8 in the 30 days before it.

After

Before

Earthquakes today Tonga earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000bjlb (also filed as iscgem618988103). Read Fri, Oct 2, 2026, 5:04 AM UTC.