M5.5 earthquake 131 km NE of Neiafu, Tonga
A magnitude 5.5 earthquake struck 131 km NE of Neiafu, Tonga on Tue, May 22, 2018, 7:30 AM GMT-12 (19:30 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
- 5.5 (Mww, W-phase moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 2018-05-22 19:30:52 UTC
- Depth
- 10.0 km (6.2 mi), shallow
- Epicenter
- 17.863° S, 173.050° W
- Region
- Tonga
- 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 |
|---|---|---|---|
| 5.5 | Mww, W-phase moment | USGS National Earthquake Information Center | Preferred · Reviewed · ±0.08 · 15 stations |
| 5.56 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.4 | 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
- 78.0% of gravity
- Peak ground velocity
- 0.4 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
- Reverse (thrust)
- Moment magnitude
- 5.5 Mww
- Nodal plane 1
- Strike 318°, dip 46°, rake 109°
- Nodal plane 2
- Strike 111°, dip 48°, rake 71°
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 6.9 km horizontally, 1.1 km in depth
- Magnitude uncertainty
- ±0.08
- Depth from
- Operator assigned
- Station coverage gap
- 40°
- Stations used
- 209
Nearby
Within 100 km, magnitude 2.5 and up: 0 in the 60 days after this one and 1 in the 30 days before it.
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us1000ea3r (also filed as iscgem611943917). Read Fri, Oct 2, 2026, 1:31 PM UTC.