M4.9 earthquake 99 km NE of Hihifo, Tonga
A magnitude 4.9 earthquake struck 99 km NE of Hihifo, Tonga on Thu, Jul 20, 1978, 8:22 PM GMT-11 (07:22 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M5.8 90 km ENE 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
- 4.9 (mb), light
- Local time
- UTC
- 1978-07-21 07:22:36 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 15.298° S, 173.168° 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
- 18
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.9 and up: 7 in the 60 days after this one and 0 in the 30 days before it.
After
- 5.488 km NE of Hihifo, Tonga · 17596 days ago · 33 km deep · 19 km away
- 5.890 km ENE of Hihifo, Tonga · 17596 days ago · 33 km deep · 35 km away
- 5.589 km NE of Hihifo, Tonga · 17591 days ago · 33 km deep · 17 km away
- 5.386 km ENE of Hihifo, Tonga · 17589 days ago · 33 km deep · 43 km away
- 4.699 km E of Hihifo, Tonga · 17559 days ago · 39 km deep · 83 km away
- 5.482 km NE of Hihifo, Tonga · 17555 days ago · 33 km deep · 19 km away
- 4.897 km NE of Hihifo, Tonga · 17551 days ago · 33 km deep · 15 km away
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0000vnx. Read Tue, Sep 29, 2026, 5:40 PM UTC.