M6.1 earthquake 105 km NE of Hihifo, Tonga
A magnitude 6.1 earthquake struck 105 km NE of Hihifo, Tonga on Wed, Aug 9, 2023, 7:38 AM GMT+13 (18:38 UTC), 42 km (26 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 6.1 (Mww, W-phase moment), strong
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 2023-08-08 18:38:54 UTC
- Depth
- 42.0 km (26.1 mi), shallow
- Epicenter
- 15.208° S, 173.188° W
- Region
- Tonga
- Felt reports
- 16
- Strongest shaking
- IV, light 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 |
|---|---|---|---|
| 6.1 | Mww, W-phase moment | USGS National Earthquake Information Center | Preferred · Reviewed · ±0.043 · 53 stations |
| 6.2 | Mi | NOAA Pacific Tsunami Warning Center | Reviewed · 11 stations |
| 6.3 | Mi | NOAA National Tsunami Warning Center | First automatic solution · Reviewed · 6 stations |
| 6.1 | Mwb, body-wave moment | USGS National Earthquake Information Center | Moment tensor · Reviewed |
| 6.1 | Mww, W-phase moment | USGS, automatic first solution | First automatic solution · Confirmed |
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- IV, light shaking
- Peak ground acceleration
- 2.8% of gravity
- Peak ground velocity
- 2.4 cm/s
- Map
- Automatic
Did you feel it?
16 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
| 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% |
| 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
- 6.1 Mww
- Nodal plane 1
- Strike 224°, dip 7°, rake -165°
- Nodal plane 2
- Strike 119°, dip 88°, rake -83°
- Landslide alert
- Green
- Liquefaction alert
- Green
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 6.5 km horizontally, 1.9 km in depth
- Magnitude uncertainty
- ±0.04
- Depth from
- From modeling of broad-band P waveforms
- Station coverage gap
- 38°
- Stations used
- 208
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 3.1 and up: 8 in the 60 days after this one and 2 in the 30 days before it.
After
- 4.4120 km NNE of Hihifo, Tonga · 1152 days ago · 37 km deep · 38 km away
- 4.5141 km NE of Hihifo, Tonga · 1141 days ago · 10 km deep · 52 km away
- 4.4118 km NE of Hihifo, Tonga · 1140 days ago · 10 km deep · 14 km away
- 4.6Tonga · 1134 days ago · 67 km deep · 76 km away
- 4.5138 km N of Hihifo, Tonga · 1132 days ago · 10 km deep · 80 km away
- 4.5111 km NNE of Hihifo, Tonga · 1127 days ago · 10 km deep · 42 km away
- 4.569 km NE of Hihifo, Tonga · 1124 days ago · 57 km deep · 36 km away
- 5.097 km NNE of Hihifo, Tonga · 1102 days ago · 16 km deep · 30 km away · felt by 1
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us6000kyph (also filed as pt23220001, usauto6000kyph, at00rz354y). Read Sat, Oct 3, 2026, 3:08 PM UTC.