M4.7 earthquake 161 km W of Neiafu, Tonga
A magnitude 4.7 earthquake struck 161 km W of Neiafu, Tonga on Sat, Apr 21, 1973, 7:21 AM GMT+13 (18:21 UTC), 159 km (99 mi) below the surface.
A larger quake followed: M5.0 116 km WNW of Neiafu, Tonga. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 4.7 (mb), light
- Local time
- UTC
- 1973-04-20 18:21:22 UTC
- Depth
- 159.0 km (98.8 mi), intermediate-depth
- Epicenter
- 18.590° S, 175.514° 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.
- Stations used
- 13
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.7 and up: 1 in the 60 days after this one and 1 in the 30 days before it.
After
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp00001fs. Read Wed, Sep 30, 2026, 8:07 PM UTC.