Reviewed by USGSNew Zealand45y ago
M5.5 earthquake in Kermadec Islands, New Zealand
Tuesday, December 29, 1981, 19:06:31 UTC · 30.240°S, 177.885°W
A magnitude 5.5 earthquake struck in Kermadec Islands, New Zealand on Tuesday, December 29, 1981, 19:06:31 UTC, at a depth of 61.0 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on December 26, 1981.
- Magnitude
- 5.5
- Moderate · mb
- Depth
- 61 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
3 kilotons of TNT
That is about 1/6 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.
Tectonic setting
123 km
from the nearest mapped plate boundary, between the Kermadec and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
61 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 75 km
USGS lists 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.4 on January 10, 1982. 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 614 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 · 159 km SE of this epicenter
- 8.01976 Kermadec Islands, New Zealand EarthquakeJanuary 14, 1976 · 203 km N of this epicenter
- 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 44 km N of this epicenter
- 7.3Kermadec Islands regionSeptember 14, 1959 · 169 km NE of this epicenter
- 7.3Kermadec Islands, New ZealandMarch 26, 1963 · 34 km NE of this epicenter
- 7.3Kermadec Islands, New ZealandJuly 25, 1968 · 67 km S of this epicenter
- 7.2Kermadec Islands regionJuly 2, 1974 · 227 km NE of this epicenter
- 7.2Kermadec Islands, New ZealandFebruary 9, 1978 · 71 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1976M7.9
Kermadec Islands
14 Jan 1976 · 124 km away
Limited damage (under $1M)tsunami
- 1968M7.3
S Of, Raoul
25 Jul 1968 · 79 km away
Limited damage (under $1M)tsunami
- 1917M8.0
Kermadec Islands
1 May 1917 · 144 km away
tsunami
- 1976M7.8
Kermadec Islands
14 Jan 1976 · 73 km away · intensity VIII
- 1959M7.7
Kermadec Islands
14 Sep 1959 · 212 km away
- 1978M7.7
S Of
9 Feb 1978 · 70 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.