Magnitude6.5

Reviewed by USGSTonga75y ago

M6.5 earthquake 124 km SSE of Hihifo, Tonga

Monday, February 25, 1952, 01:17:09 UTC · 17.005°S, 173.369°W

A magnitude 6.5 earthquake struck 124 km SSE of Hihifo, Tonga on Monday, February 25, 1952, 01:17:09 UTC, at a depth of 41.8 km (shallow). It is the strongest earthquake within 300 km since an M6.7 on November 27, 1949.

Magnitude
6.5
Strong · mw
Depth
42 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

74 kilotons of TNT

That is about 5 times the Hiroshima bomb. It released about 155 times the energy of a magnitude 5.0.

Tectonic setting

109 km

from the nearest mapped plate boundary, between the Tonga and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

42 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 66 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

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, which together caused about 2 recorded deaths. The most severe:

  1. 1917M8.3

    Samoa Islands

    26 Jun 1917 · 172 km away

    2 deathsModerate damage ($1–5M)tsunami

  2. 1919M8.1

    Tonga Islands

    30 Apr 1919 · 175 km away

    Limited damage (under $1M)tsunami

  3. 1865M8.0

    Tonga Islands

    18 Nov 1865 · 278 km away

    Limited damage (under $1M)tsunami

  4. 1949M6.9

    Tonga Islands

    6 Aug 1949 · 257 km away

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

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