M5.6 earthquake 77 km WNW of Haveluloto, Tonga
A magnitude 5.6 earthquake struck 77 km WNW of Haveluloto, Tonga on Sat, Dec 24, 1983, 3:35 AM GMT+13 (14:35 UTC), 33 km (21 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.6 (Ms, surface-wave), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1983-12-23 14:35:54 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 20.899° S, 175.913° 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 |
|---|---|---|---|
| 5.6 | Ms, surface-wave | USGS National Earthquake Information Center | Preferred · Reviewed · 1 stations |
| 5.52 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.5 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME B122383A DATA USED: GDSN L.P. BODY WAVES: 15S, 34C, T=45 CENTROID LOCATION: ORIGIN TIME 14:35:52.3 0.3 LAT 21.28S 0.04;LON 175.79W 0.04 DEP 10.1 FIX;HALF-DURATION 2.2 MOMENT TENSOR; SCALE 10**24 D-CM MRR=2.44 0.06; MTT=-0.66 0.08 MFF=-1.78 0.08; MRT=-0.12 0.25 MRF=0.92 0.33; MTF=0.43 0.07 PRINCIPAL AXES: 1.(T) VAL=2.63;PLG=78;AZM=268 2.(N) -0.52; 3; 163 3.(P) -2.11; 11; 73 BEST DOUBLE COUPLE:M0=2.4*10**24 NP1:STRIKE=159;DIP=34;SLIP=85 NP2:Strike=345;Dip=56;Slip=94
From the USGS event page for usp00020rd. U.S. Geological Survey text and figures are in the public domain.
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
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.6 and up: 0 in the 60 days after this one and 1 in the 30 days before it.
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp00020rd (also filed as gcmtb122383a, gcmt19831223143555, iscgem563502). Read Sat, Oct 3, 2026, 3:32 PM UTC.