M5.5 earthquake 145 km ESE of Hihifo, Tonga
A magnitude 5.5 earthquake struck 145 km ESE of Hihifo, Tonga on Sun, Dec 6, 1987, 1:00 PM GMT-11 (00:00 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
- 5.5 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1987-12-07 00:00:15 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 16.613° S, 172.613° 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 | Mw, moment | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.48 | 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 (HRV) Data Used: GDSN L.P.B.: 12S, 22C Centroid Location: Origin Time 00:00:16.8 0.7 Lat 16.98S 0.10 Lon 172.68W 0.12 Dep 15.0 FIX Half-duration 2.0 Moment Tensor; Scale 10**17 Nm Mrr=0.48 0.07 Mtt=-0.06 0.06 Mff=-0.42 0.10 Mrt=0.53 0.14 Mrf=1.90 0.15 Mtf=-0.12 0.06 Principal Axes: (T) Val=2.04 Plg=52 Azm=285 (N) Val=-0.03 Plg=0 Azm=16 (P) Val=-2.02 Plg=38 Azm=106 Best Double Couple:Mo=2.0*10**17 NP1:Strike=198 Dip=7 Slip=93 NP2:Strike=15 Dip=83 Slip=90
From the USGS event page for usp0003b14. 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 2.5 and up: 3 in the 60 days after this one and 4 in the 30 days before it.
After
- 5.4163 km SE of Hihifo, Tonga · 14160 days ago · 26 km deep · 26 km away
- 5.078 km SE of Hihifo, Tonga · 14152 days ago · 33 km deep · 75 km away
- 4.483 km SE of Hihifo, Tonga · 14152 days ago · 33 km deep · 73 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0003b14 (also filed as gcmtb120787a, gcmt19871207000014, iscgem450013). Read Thu, Oct 1, 2026, 11:10 AM UTC.