Reviewed by USGSNew Zealand59y ago
M6.4 earthquake in Kermadec Islands, New Zealand
Thursday, May 30, 1968, 19:42:26 UTC · 30.921°S, 177.503°W
A magnitude 6.4 earthquake struck in Kermadec Islands, New Zealand on Thursday, May 30, 1968, 19:42:26 UTC, at a depth of 35.4 km (shallow). It is the strongest earthquake within 300 km since an M6.9 on May 20, 1968.
- Magnitude
- 6.4
- Strong · mw
- Depth
- 35 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
60 kilotons of TNT
That is about 4 times the Hiroshima bomb. It released about 126 times the energy of a magnitude 5.0.
Tectonic setting
57 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
35 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 2 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.7 on June 9, 1968. 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 176 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 · 87 km E of this epicenter
- 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 123 km N of this epicenter
- 7.3Kermadec Islands regionSeptember 14, 1959 · 233 km N of this epicenter
- 7.3Kermadec Islands, New ZealandMarch 26, 1963 · 105 km N of this epicenter
- 7.2Kermadec Islands, New ZealandAugust 2, 1941 · 127 km N of this epicenter
- 7.2Kermadec Islands, New ZealandApril 17, 1919 · 60 km NW of this epicenter
- 7.1Kermadec Islands, New ZealandJune 29, 1910 · 39 km E of this epicenter
- 7.1Kermadec Islands, New ZealandSeptember 16, 1941 · 204 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1968M7.3
S Of, Raoul
25 Jul 1968 · 87 km away
Limited damage (under $1M)tsunami
- 1917M8.0
Kermadec Islands
1 May 1917 · 197 km away
tsunami
- 1959M7.7
Kermadec Islands
14 Sep 1959 · 274 km away
- 1943M7.6
S Of
14 Sep 1943 · 113 km away
- 1917M7.5
S Of
16 Nov 1917 · 214 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.