Reviewed by USGSTonga72y ago
M6.7 earthquake 255 km W of Haveluloto, Tonga
Saturday, August 6, 1955, 08:31:32 UTC · 20.955°S, 177.666°W
A magnitude 6.7 earthquake struck 255 km W of Haveluloto, Tonga on Saturday, August 6, 1955, 08:31:32 UTC, at a depth of 360.2 km (deep). It is the strongest earthquake within 300 km since an M7.8 on December 14, 1950.
- Magnitude
- 6.7
- Strong · mw
- Depth
- 360 km
- Deep
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
169 kilotons of TNT
That is about 11 times the Hiroshima bomb. It released about 355 times the energy of a magnitude 5.0.
Tectonic setting
140 km
from the nearest mapped plate boundary, between the Tonga and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: deep
360 km
Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 25 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.0TongaJanuary 4, 1903 · 297 km E of this epicenter
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 233 km NE of this epicenter
- 7.8Fiji regionJanuary 1, 1919 · 187 km N of this epicenter
- 7.3227 km WNW of Haveluloto, TongaApril 16, 1937 · 54 km NE of this epicenter
- 7.3Fiji regionMay 25, 1944 · 196 km W of this epicenter
- 7.2241 km WNW of Houma, TongaAugust 21, 1911 · 114 km N of this epicenter
- 7.2280 km WNW of Houma, TongaDecember 14, 1910 · 71 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1937M8.1
Fiji Islands
16 Apr 1937 · 92 km away
- 1903M8.0
Tonga Islands
4 Jan 1903 · 297 km away
- 1919M7.8
Fiji Islands
1 Jan 1919 · 187 km away
tsunami
- 1950M7.7
Tonga Islands
14 Dec 1950 · 237 km away · intensity VI
- 1853
Tonga Trench
24 Dec 1853 · 260 km away
tsunami
- 1907
S Of Tonga
1907 · 202 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.