Reviewed by USGSNew Zealand51y ago
M6.8 earthquake in Kermadec Islands, New Zealand
Wednesday, March 24, 1976, 04:46:04 UTC · 29.887°S, 177.873°W
A magnitude 6.8 earthquake struck in Kermadec Islands, New Zealand on Wednesday, March 24, 1976, 04:46:04 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M8.0 on January 14, 1976.
- Magnitude
- 6.8
- Strong · ms
- 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
239 kilotons of TNT
That is about 16 times the Hiroshima bomb. It released about 501 times the energy of a magnitude 5.0.
Tectonic setting
114 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
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 100 km
USGS lists 8 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.8 on March 27, 1976. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6Kermadec Islands, New Zealand51y ago · 52 km E of this epicenter
- 4.5Kermadec Islands, New Zealand51y ago · 80 km E of this epicenter
- 5.3Kermadec Islands, New Zealand51y ago · 72 km NE of this epicenter
- 5.1Kermadec Islands, New Zealand51y ago · 95 km S of this epicenter
- 5.1Kermadec Islands, New Zealand51y ago · 41 km S of this epicenter
- 5.8Kermadec Islands, New Zealand51y ago · 83 km S of this epicenter
- 5.4Kermadec Islands, New Zealand51y ago · 33 km S of this epicenter
- 4.7Kermadec Islands, New Zealand51y ago · 12 km N of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 343 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 · 187 km SE of this epicenter
- 8.01976 Kermadec Islands, New Zealand EarthquakeJanuary 14, 1976 · 164 km N of this epicenter
- 7.5Kermadec Islands regionFebruary 27, 1955 · 280 km NE of this epicenter
- 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 5 km NE of this epicenter
- 7.3Kermadec Islands regionSeptember 14, 1959 · 133 km NE of this epicenter
- 7.3Kermadec Islands, New ZealandMarch 26, 1963 · 22 km SE of this epicenter
- 7.3Kermadec Islands, New ZealandJuly 25, 1968 · 105 km S of this epicenter
- 7.2Kermadec Islands regionJuly 2, 1974 · 206 km NE 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 · 88 km away
Limited damage (under $1M)tsunami
- 1968M7.3
S Of, Raoul
25 Jul 1968 · 113 km away
Limited damage (under $1M)tsunami
- 1917M8.0
Kermadec Islands
1 May 1917 · 114 km away
tsunami
- 1976M7.8
Kermadec Islands
14 Jan 1976 · 63 km away · intensity VIII
- 1959M7.7
Kermadec Islands
14 Sep 1959 · 176 km away
- 1943M7.6
S Of
14 Sep 1943 · 85 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.