M5.5 earthquake 29 km WNW of Hihifo, Tonga
A magnitude 5.5 earthquake struck 29 km WNW of Hihifo, Tonga on Sun, Jan 21, 1973, 9:20 AM GMT-11 (20:20 UTC), 129 km (80 mi) below the surface.
A larger quake followed: M5.8 87 km NE of Hihifo, 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 (mb, body-wave), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1973-01-21 20:20:49 UTC
- Depth
- 129.0 km (80.2 mi), intermediate-depth
- Epicenter
- 15.857° S, 174.055° W
- Region
- Tonga
- 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 | mb, body-wave | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.55 | Mw, moment | ISC-GEM global catalog | Final · ±0.21 |
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Stations used
- 78
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.5 and up: 5 in the 60 days after this one and 2 in the 30 days before it.
After
- 5.161 km S of Hihifo, Tonga · 19605 days ago · 33 km deep · 79 km away
- 5.887 km NE of Hihifo, Tonga · 19587 days ago · 50 km deep · 100 km away
- 5.381 km NE of Hihifo, Tonga · 19579 days ago · 33 km deep · 96 km away
- 5.690 km NNE of Hihifo, Tonga · 19564 days ago · 8 km deep · 94 km away
- 4.622 km SSE of Hihifo, Tonga · 19553 days ago · 86 km deep · 48 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp000008b (also filed as iscgem765157). Read Fri, Oct 2, 2026, 6:21 PM UTC.