Reviewed by USGSFiji22y ago
M3.9 earthquake 266 km E of Levuka, Fiji
Wednesday, October 20, 2004, 05:46:34 UTC · 18.371°S, 178.186°W
A magnitude 3.9 earthquake struck 266 km E of Levuka, Fiji on Wednesday, October 20, 2004, 05:46:34 UTC, at a depth of 401.8 km (deep).
- Magnitude
- 3.9
- Minor · mb
- Depth
- 402 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
11 tons of TNT
That is about 1/1,410 of the Hiroshima bomb. A magnitude 5.0 releases about 45 times more energy.
Tectonic setting
175 km
from the nearest mapped plate boundary, between the Niuafo'ou and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: deep
402 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 50 km
USGS lists 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.8 on October 31, 2004. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,165 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 285 km SE of this epicenter
- 7.8Fiji regionJanuary 1, 1919 · 106 km S of this epicenter
- 7.6178 km E of Levuka, FijiFebruary 22, 1909 · 88 km W of this epicenter
- 7.6240 km E of Levuka, FijiMarch 9, 1994 · 44 km NW of this epicenter
- 7.5262 km WNW of Haveluloto, TongaMay 21, 1962 · 206 km S of this epicenter
- 7.4227 km E of Levuka, FijiAugust 21, 1910 · 73 km NW of this epicenter
- 7.4Fiji regionSeptember 28, 1957 · 242 km S of this epicenter
- 7.4Fiji regionAugust 5, 1996 · 258 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1919M6.9
Rabi,Tunuloa Mission,Suvasavu
3 Oct 1919 · 292 km away · intensity VIII
Moderate damage ($1–5M)
- 1979M6.9
Fiji Islands
16 Nov 1979 · 262 km away
Moderate damage ($1–5M)tsunami
- 1932M6.4
Koro,Mudu,Suvasavu
8 Mar 1932 · 218 km away · intensity VII
Moderate damage ($1–5M)
- 1909M7.8
Fiji Islands
22 Feb 1909 · 95 km away
- 1919M7.8
Fiji Islands
1 Jan 1919 · 106 km away
tsunami
- 1950M7.7
Tonga Islands
14 Dec 1950 · 262 km away · intensity VI
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.