M5.5 earthquake 121 km E of ‘Ohonua, Tonga
A magnitude 5.5 earthquake struck 121 km E of ‘Ohonua, Tonga on Sun, May 13, 2018, 6:50 PM GMT+13 (05:50 UTC), 10 km (6 mi) below the surface.
A larger quake followed: M5.6 104 km ENE of ‘Ohonua, Tonga. This one was a foreshock.
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
- 2018-05-13 05:50:33 UTC
- Depth
- 10.0 km (6.2 mi), shallow
- Epicenter
- 21.164° S, 173.797° 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 · ±0.062 · 25 stations |
| 5.54 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.5 | 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
- 49.0% of gravity
- Peak ground velocity
- 0.6 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 196°, dip 37°, rake 73°
- Nodal plane 2
- Strike 37°, dip 54°, rake 102°
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 6.5 km horizontally, 1.6 km in depth
- Magnitude uncertainty
- ±0.06
- Depth from
- Operator assigned
- Station coverage gap
- 79°
- Stations used
- 113
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.5 and up: 9 in the 60 days after this one and 3 in the 30 days before it.
After
- 4.9102 km SE of Pangai, Tonga · 3064 days ago · 26 km deep · 79 km away
- 4.677 km SSE of Pangai, Tonga · 3059 days ago · 10 km deep · 87 km away
- 5.6104 km ENE of ‘Ohonua, Tonga · 3058 days ago · 10 km deep · 22 km away
- 5.0118 km ENE of ‘Ohonua, Tonga · 3058 days ago · 10 km deep · 23 km away
- 4.796 km E of ‘Ohonua, Tonga · 3057 days ago · 35 km deep · 30 km away
- 4.6125 km E of ‘Ohonua, Tonga · 3047 days ago · 10 km deep · 6 km away
- 4.996 km SE of Pangai, Tonga · 3014 days ago · 10 km deep · 92 km away
- 5.0112 km SE of Pangai, Tonga · 3013 days ago · 10 km deep · 92 km away
- 4.9104 km SSE of Pangai, Tonga · 3010 days ago · 10 km deep · 62 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us1000e3zd (also filed as iscgem616639242). Read Sat, Oct 3, 2026, 3:46 AM UTC.