Reviewed by USGS63y ago
M6.1 earthquake south of the Fiji Islands
Tuesday, July 21, 1964, 03:48:58 UTC · 25.845°S, 177.840°W
A magnitude 6.1 earthquake struck south of the Fiji Islands on Tuesday, July 21, 1964, 03:48:58 UTC, at a depth of 205.0 km (intermediate). It is the strongest earthquake within 300 km since an M7.6 on December 18, 1963.
- Magnitude
- 6.1
- Strong · mw
- Depth
- 205 km
- Intermediate
- 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
24 kilotons of TNT
That is about 2 times the Hiroshima bomb. It released about 51 times the energy of a magnitude 5.0.
Tectonic setting
7 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: intermediate
205 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 63 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.6south of the Fiji IslandsDecember 18, 1963 · 158 km NE of this epicenter
- 7.2south of the Fiji IslandsNovember 24, 1960 · 206 km NE of this epicenter
- 7.0south of TongaJanuary 10, 1956 · 267 km E of this epicenter
- 6.8south of the Fiji IslandsJuly 4, 1963 · 69 km S of this epicenter
- 6.7south of the Fiji IslandsSeptember 8, 1920 · 218 km NE of this epicenter
- 6.7Kermadec Islands regionNovember 24, 1941 · 279 km S of this epicenter
- 6.7Kermadec Islands regionMay 4, 1917 · 235 km SE of this epicenter
- 6.6south of the Fiji IslandsNovember 23, 1960 · 210 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 3 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1932M7.9
Kermadec Islands
26 May 1932 · 299 km away
- 1963M7.5
Tonga Trench
18 Dec 1963 · 170 km away
tsunami
- 1956M7.0
Tonga Islands
10 Jan 1956 · 260 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.