Reviewed by USGSTonga84y ago
M6.5 earthquake 176 km SE of ‘Ohonua, Tonga
Sunday, October 24, 1943, 16:04:39 UTC · 22.576°S, 173.876°W
A magnitude 6.5 earthquake struck 176 km SE of ‘Ohonua, Tonga on Sunday, October 24, 1943, 16:04:39 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.5 on November 2, 1942.
- Magnitude
- 6.5
- Strong · mw
- Depth
- 15 km
- Shallow
- 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
85 kilotons of TNT
That is about 6 times the Hiroshima bomb. It released about 178 times the energy of a magnitude 5.0.
Tectonic setting
39 km
from the nearest mapped plate boundary, between the Tonga and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
15 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 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 30 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8111 km SSE of Pangai, TongaJune 26, 1913 · 211 km N of this epicenter
- 7.4south of TongaMarch 18, 1905 · 205 km S of this epicenter
- 6.597 km WSW of Pangai, TongaNovember 2, 1942 · 296 km NW of this epicenter
- 6.577 km SSW of Pangai, TongaJune 24, 1917 · 253 km N of this epicenter
- 6.5TongaDecember 18, 1906 · 95 km N of this epicenter
- 6.5TongaFebruary 14, 1930 · 147 km NW of this epicenter
- 6.420 km SSW of Pangai, TongaJune 1, 1930 · 292 km N of this epicenter
- 6.3114 km SSE of Pangai, TongaMay 22, 1932 · 201 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 4 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1902M7.8
Tonga Islands
9 Feb 1902 · 287 km away
- 1913M7.6
Tonga Islands
26 Jun 1913 · 287 km away
- 1853
Tonga Trench
24 Dec 1853 · 206 km away
tsunami
- 1907
S Of Tonga
1907 · 247 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.