Reviewed by USGSNew Zealand region46y ago
M4.6 earthquake in Auckland Islands, New Zealand region
Monday, May 25, 1981, 21:59:02 UTC · 49.260°S, 164.177°E
A magnitude 4.6 earthquake struck in Auckland Islands, New Zealand region on Monday, May 25, 1981, 21:59:02 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.7 on May 25, 1981.
- Magnitude
- 4.6
- Light · mb
- Depth
- 33 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
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
27 km
from the nearest mapped plate boundary, between the Pacific and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
33 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 M5.7 on May 30, 1981. 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 35 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.6off the west coast of the South Island of New ZealandMay 25, 1981 · 54 km N of this epicenter
- 7.5173 km WSW of Riverton, New ZealandSeptember 1, 1945 · 285 km NE of this epicenter
- 7.0Auckland Islands, New Zealand regionSeptember 12, 1964 · 30 km NE of this epicenter
- 7.0Auckland Islands, New Zealand regionJanuary 5, 1955 · 132 km SW of this epicenter
- 7.0Auckland Islands, New Zealand regionFebruary 22, 1936 · 12 km N of this epicenter
- 6.8off the west coast of the South Island of New ZealandJanuary 12, 1954 · 83 km NE of this epicenter
- 6.7Auckland Islands, New Zealand regionMarch 18, 1961 · 88 km SW of this epicenter
- 6.7off the west coast of the South Island of New ZealandJanuary 13, 1954 · 101 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1926M7.9
Macquarie Island: North Of
3 Oct 1926 · 233 km away
- 1981M7.6
W Of North Island
25 May 1981 · 54 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.