QuakeScout
Magnitude4.5

Reviewed by USGS18y ago

M4.5 earthquake in Kermadec Islands region

Sunday, December 21, 2008, 23:39:12 UTC · 30.980°S, 176.615°W

A magnitude 4.5 earthquake struck in Kermadec Islands region on Sunday, December 21, 2008, 23:39:12 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M5.0 on December 20, 2008.

Magnitude
4.5
Light · mb
Depth
10 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

85 tons of TNT

That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.

Tectonic setting

22 km

from the nearest mapped plate boundary, between the Kermadec and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

10 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.4 on December 26, 2008. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M41h6h1d3d7d14d30dMainshock M4.5
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 region18y ago · 16 km SW of this epicenter
  2. 4.2Kermadec Islands region18y ago · 38 km N of this epicenter
  3. 4.2Kermadec Islands region18y ago · 45 km N of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,490 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.21917 Kermadec Islands, New Zealand EarthquakeMay 1, 1917 · 24 km S of this epicenter
  2. 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 172 km NW of this epicenter
  3. 7.4Kermadec Islands regionMay 16, 2006 · 272 km W of this epicenter
  4. 7.3Kermadec Islands regionSeptember 14, 1959 · 245 km N of this epicenter
  5. 7.3Kermadec Islands, New ZealandMarch 26, 1963 · 150 km NW of this epicenter
  6. 7.3Kermadec Islands, New ZealandJuly 25, 1968 · 147 km W of this epicenter
  7. 7.2Kermadec Islands regionJuly 2, 1974 · 220 km N of this epicenter
  8. 7.2Kermadec Islands, New ZealandFebruary 9, 1978 · 78 km NW of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1976M7.9

    Kermadec Islands

    14 Jan 1976 · 214 km away

    Limited damage (under $1M)tsunami

  2. 1968M7.3

    S Of, Raoul

    25 Jul 1968 · 171 km away

    Limited damage (under $1M)tsunami

  3. 1917M8.0

    Kermadec Islands

    1 May 1917 · 201 km away

    tsunami

  4. 1976M7.8

    Kermadec Islands

    14 Jan 1976 · 131 km away · intensity VIII

  5. 1959M7.7

    Kermadec Islands

    14 Sep 1959 · 278 km away

  6. 1978M7.7

    S Of

    9 Feb 1978 · 79 km away

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

Nearby trackers

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