Tonga earthquakes

M6.8 earthquake 97 km NE of Hihifo, Tonga

A magnitude 6.8 earthquake struck 97 km NE of Hihifo, Tonga on Sat, Nov 4, 2017, 11:00 PM GMT+14 (09:00 UTC), 10 km (6 mi) below the surface.

Apia forecast More in Tonga

Map

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

Open the live map with earthquakes

The earthquake

Magnitude: 6.8 (Mww, W-phase moment), strong
Magnitude from: USGS National Earthquake Information Center
Local time: Sat, Nov 4, 2017, 11:00 PM GMT+14
UTC: 2017-11-04 09:00:19 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 15.320° S, 173.168° W
Region: Tonga
Felt reports: 35
Strongest shaking: V, moderate shaking
PAGER alert: Green
Tsunami flag: Yes: a large quake in an oceanic region
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
6.8	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.044 · 50 stations
6.71	Mw, moment	ISC-GEM global catalog	Final · ±0.1
6.9	Mi	NOAA National Tsunami Warning Center	Reviewed · 28 stations
6.9	Mi	NOAA Pacific Tsunami Warning Center	Reviewed · 16 stations
6.5	Mwb, body-wave moment	USGS National Earthquake Information Center	Moment tensor · Reviewed

Tsunami

The USGS flags a quake this large in an oceanic region. The flag does not mean a tsunami happened; the tsunami warning centers decide that, and their messages are below when they issued any.

Current tsunami warnings: tsunami.gov. Warnings in force in the US also appear on our alerts pages.

Shaking

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

Strongest estimated: V, moderate shaking
Peak ground acceleration: 492.0% of gravity
Peak ground velocity: 6.8 cm/s
Map: Automatic

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

Did you feel it?

35 people reported to the USGS what they felt; the strongest reported shaking was V, moderate 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: 6.8 Mww
Nodal plane 1: Strike 178°, dip 23°, rake 166°
Nodal plane 2: Strike 280°, dip 85°, rake 68°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 8.1 km horizontally, 1.7 km in depth
Magnitude uncertainty: ±0.04
Depth from: Operator assigned
Station coverage gap: 21°
Stations used: 148

Nearest places

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

Apia, SamoaPopulation 40,407. Forecast224 kmSW

Nearby

Within 100 km, magnitude 3.8 and up: 24 in the 60 days after this one and 11 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 us2000bibm (also filed as at00oyvycj, pt17308000, iscgem611835219). Read Fri, Oct 2, 2026, 9:59 AM UTC.