Reviewed by USGS5y ago
M4.2 earthquake in Kermadec Islands region
Sunday, September 12, 2021, 05:19:34 UTC · 30.239°S, 176.381°W
A magnitude 4.2 earthquake struck in Kermadec Islands region on Sunday, September 12, 2021, 05:19:34 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 4.2
- 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 earthquake
In context
How big was it, and why here?
Energy released
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
12 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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 2,251 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21917 Kermadec Islands, New Zealand EarthquakeMay 1, 1917 · 109 km S of this epicenter
- 8.12021 Kermadec Islands, New Zealand EarthquakeMarch 4, 2021 · 104 km NW of this epicenter
- 8.01976 Kermadec Islands, New Zealand EarthquakeJanuary 14, 1976 · 236 km NW of this epicenter
- 7.7Kermadec Islands regionOctober 20, 1986 · 236 km N of this epicenter
- 7.6Kermadec Islands regionJuly 6, 2011 · 78 km N of this epicenter
- 7.5Kermadec Islands regionFebruary 27, 1955 · 225 km N of this epicenter
- 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 147 km W of this epicenter
- 7.4Kermadec Islands, New ZealandMarch 4, 2021 · 154 km NW 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:
- 1986M8.1
Raoul
20 Oct 1986 · 236 km away
Limited damage (under $1M)tsunami
- 1976M7.9
Kermadec Islands
14 Jan 1976 · 155 km away
Limited damage (under $1M)tsunami
- 1968M7.3
S Of, Raoul
25 Jul 1968 · 203 km away
Limited damage (under $1M)tsunami
- 2021M8.1
Sse Of Raoul Island
4 Mar 2021 · 102 km away · intensity IX
tsunami
- 1917M8.0
Kermadec Islands
1 May 1917 · 130 km away
tsunami
- 1955M7.8
Kermadec Islands
27 Feb 1955 · 263 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.