M5.6 earthquake 91 km NW of Hihifo, Tonga
A magnitude 5.6 earthquake struck 91 km NW of Hihifo, Tonga on Mon, Apr 23, 2018, 5:59 AM GMT+13 (16:59 UTC), 10 km (6 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.6 (Mww, W-phase moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 2018-04-22 16:59:16 UTC
- Depth
- 10.0 km (6.2 mi), shallow
- Epicenter
- 15.463° S, 174.484° W
- Region
- Tonga
- 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 |
|---|---|---|---|
| 5.6 | Mww, W-phase moment | USGS National Earthquake Information Center | Preferred · Reviewed · ±0.071 · 19 stations |
| 5.68 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.7 | 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
- IV, light shaking
- Peak ground acceleration
- 119.0% of gravity
- Peak ground velocity
- 1.5 cm/s
- Map
- Automatic
Did you feel it?
No one has reported feeling this quake to the USGS.
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
- 5.6 Mww
- Nodal plane 1
- Strike 83°, dip 79°, rake 8°
- Nodal plane 2
- Strike 351°, dip 82°, rake 169°
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 10.7 km horizontally, 1.8 km in depth
- Magnitude uncertainty
- ±0.07
- Depth from
- Operator assigned
- Station coverage gap
- 58°
- Stations used
- 87
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.6 and up: 5 in the 60 days after this one and 4 in the 30 days before it.
After
- 4.0156 km NW of Hihifo, Tonga · 3058 days ago · 253 km deep · 66 km away
- 4.3148 km NW of Hihifo, Tonga · 3044 days ago · 199 km deep · 58 km away
- 4.2135 km NW of Hihifo, Tonga · 3029 days ago · 149 km deep · 48 km away
- 4.2123 km W of Hihifo, Tonga · 3028 days ago · 249 km deep · 68 km away
- 5.139 km WSW of Hihifo, Tonga · 3026 days ago · 120 km deep · 85 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us1000dqc2 (also filed as iscgem611889124). Read Fri, Oct 2, 2026, 1:49 PM UTC.