Magnitude7.3

Reviewed by USGS68y ago

M7.3 earthquake in Kermadec Islands region

Monday, September 14, 1959, 14:09:46 UTC · 28.840°S, 177.209°W

A magnitude 7.3 earthquake struck in Kermadec Islands region on Monday, September 14, 1959, 14:09:46 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.5 on February 27, 1955.

Magnitude
7.3
Major · mw
Depth
35 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 earthquakeDashed circle: 200 km aftershock search area

In context

How big was it, and why here?

Energy released

1.4 megatons of TNT

That is about 92 times the Hiroshima bomb. It released about 2,917 times the energy of a magnitude 5.0.

Tectonic setting

113 km

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

Depth: shallow

35 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 lists 8 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.8 on September 15, 1959. 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 86 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 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1917M8.0

    Kermadec Islands

    1 May 1917 · 45 km away

    tsunami

  2. 1955M7.8

    Kermadec Islands

    27 Feb 1955 · 191 km away

  3. 1959M7.7

    Kermadec Islands

    14 Sep 1959 · 43 km away

  4. 1943M7.6

    S Of

    14 Sep 1943 · 131 km away

  5. 1917M7.5

    S Of

    16 Nov 1917 · 33 km away

    tsunami

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

Nearby trackers

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