M5.1 earthquake 135 km NNE of Hihifo, Tonga
A magnitude 5.1 earthquake struck 135 km NNE of Hihifo, Tonga on Sat, Aug 20, 1977, 5:44 PM GMT-11 (04:44 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M5.4 94 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
- 5.1 (ms), moderate
- Local time
- UTC
- 1977-08-21 04:44:32 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 14.773° S, 173.474° W
- Region
- Tonga
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Depth from
- OPERATOR_ASSIGNED
- Stations used
- 25
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.1 and up: 8 in the 60 days after this one and 1 in the 30 days before it.
After
- 5.494 km NE of Hihifo, Tonga · 17916 days ago · 18 km deep · 63 km away
- 5.688 km NE of Hihifo, Tonga · 17908 days ago · 33 km deep · 74 km away
- 5.681 km NE of Hihifo, Tonga · 17908 days ago · 33 km deep · 72 km away
- 6.077 km NE of Hihifo, Tonga · 17906 days ago · 33 km deep · 78 km away
- 4.885 km NNE of Hihifo, Tonga · 17906 days ago · 33 km deep · 55 km away
- 5.197 km ENE of Hihifo, Tonga · 17906 days ago · 33 km deep · 91 km away
- 5.1132 km ENE of Hihifo, Tonga · 17906 days ago · 4 km deep · 96 km away
- 4.468 km ENE of Hihifo, Tonga · 17899 days ago · 33 km deep · 99 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0000q83. Read Tue, Sep 22, 2026, 11:01 AM UTC.