Reviewed by USGS63y ago
M7.6 earthquake south of the Fiji Islands
Wednesday, December 18, 1963, 00:30:05 UTC · 24.749°S, 176.844°W
A magnitude 7.6 earthquake struck south of the Fiji Islands on Wednesday, December 18, 1963, 00:30:05 UTC, at a depth of 55.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.6
- Major · mw
- Depth
- 55 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VIII
- Severe (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
3.8 megatons of TNT
That is about 252 times the Hiroshima bomb. It released about 7,943 times the energy of a magnitude 5.0.
Tectonic setting
71 km
from the nearest mapped plate boundary, between the Kermadec and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
55 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
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 200 km
USGS has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 57 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.2south of the Fiji IslandsNovember 24, 1960 · 61 km E of this epicenter
- 7.0south of TongaJanuary 10, 1956 · 247 km SE of this epicenter
- 6.8south of the Fiji IslandsJuly 4, 1963 · 217 km SW of this epicenter
- 6.7south of the Fiji IslandsSeptember 8, 1920 · 62 km NE of this epicenter
- 6.6south of the Fiji IslandsNovember 23, 1960 · 58 km E of this epicenter
- 6.5Kermadec Islands regionOctober 8, 1929 · 262 km S of this epicenter
- 6.4south of TongaMarch 20, 1961 · 139 km NE of this epicenter
- 6.4283 km SSW of ‘Ohonua, TongaSeptember 30, 1949 · 143 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1963M7.5
Tonga Trench
18 Dec 1963 · 25 km away
tsunami
- 1956M7.0
Tonga Islands
10 Jan 1956 · 213 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.