QuakeScout
Magnitude4.3

Reviewed by USGS5y ago

M4.3 earthquake in Kermadec Islands region

Tuesday, September 14, 2021, 18:05:13 UTC · 28.312°S, 177.025°W

A magnitude 4.3 earthquake struck in Kermadec Islands region on Tuesday, September 14, 2021, 18:05:13 UTC, at a depth of 12.0 km (shallow).

Magnitude
4.3
Light · mb
Depth
12 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: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

43 tons of TNT

That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.

Tectonic setting

108 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

12 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 50 km

USGS lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.4 on September 23, 2021. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M41h6h1d3d7d14d30dMainshock M4.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.4Kermadec Islands region5y ago · 41 km S of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 2,139 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.12021 Kermadec Islands, New Zealand EarthquakeMarch 4, 2021 · 159 km S of this epicenter
  2. 8.01976 Kermadec Islands, New Zealand EarthquakeJanuary 14, 1976 · 63 km W of this epicenter
  3. 7.8south of the Fiji IslandsDecember 9, 2007 · 262 km N of this epicenter
  4. 7.7Kermadec Islands regionOctober 20, 1986 · 68 km E of this epicenter
  5. 7.6Kermadec Islands regionJuly 6, 2011 · 152 km SE of this epicenter
  6. 7.5Kermadec Islands regionFebruary 27, 1955 · 140 km E of this epicenter
  7. 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 188 km SW of this epicenter
  8. 7.4Kermadec Islands, New ZealandMarch 4, 2021 · 171 km SW of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 19 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1986M8.1

    Raoul

    20 Oct 1986 · 68 km away

    Limited damage (under $1M)tsunami

  2. 1976M7.9

    Kermadec Islands

    14 Jan 1976 · 106 km away

    Limited damage (under $1M)tsunami

  3. 2021M8.1

    Sse Of Raoul Island

    4 Mar 2021 · 161 km away · intensity IX

    tsunami

  4. 1917M8.0

    Kermadec Islands

    1 May 1917 · 99 km away

    tsunami

  5. 1955M7.8

    Kermadec Islands

    27 Feb 1955 · 153 km away

  6. 1976M7.8

    Kermadec Islands

    14 Jan 1976 · 180 km away · intensity VIII

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

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