M5.5 earthquake 127 km ENE of ‘Ohonua, Tonga
A magnitude 5.5 earthquake struck 127 km ENE of ‘Ohonua, Tonga on Sun, Feb 28, 1988, 2:46 AM GMT+13 (13:46 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M5.9 110 km E of ‘Ohonua, Tonga. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.5 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1988-02-27 13:46:15 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 21.022° S, 173.764° 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 |
| 5.5 | 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.: 10S, 22C Centroid Location: Origin Time 13:46:18.7 0.5 Lat 21.16S 0.05 Lon 173.54W 0.05 Dep 15.0 FIX Half-duration 2.2 Moment Tensor; Scale 10**17 Nm Mrr=1.65 0.05 Mtt=0.21 0.08 Mff=-1.85 0.07 Mrt=0.57 0.18 Mrf=1.15 0.25 Mtf=-0.20 0.06 Principal Axes: (T) Val=2.12 Plg=69 Azm=314 (N) Val=0.13 Plg=12 Azm=192 (P) Val=-2.25 Plg=17 Azm=99 Best Double Couple:Mo=2.2*10**17 NP1:Strike=171 Dip=29 Slip=66 NP2:Strike=18 Dip=63 Slip=103
From the USGS event page for usp0003ddk. 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: 2 in the 60 days after this one and 2 in the 30 days before it.
After
- 4.3117 km E of ‘Ohonua, Tonga · 14096 days ago · 33 km deep · 45 km away
- 5.9110 km E of ‘Ohonua, Tonga · 14080 days ago · 40 km deep · 45 km away
Before
Earthquakes todayTonga earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0003ddk (also filed as gcmtb022788b, gcmt19880227134616, iscgem446592). Read Sun, Oct 4, 2026, 7:39 AM UTC.