Reviewed by USGS52y ago
M5.0 earthquake in Kermadec Islands region
Monday, July 15, 1974, 11:07:57 UTC · 29.364°S, 176.475°W
A magnitude 5.0 earthquake struck in Kermadec Islands region on Monday, July 15, 1974, 11:07:57 UTC, at a depth of 78.0 km (intermediate). It is the strongest earthquake within 300 km since an M5.3 on July 14, 1974.
- Magnitude
- 5.0
- Moderate · mb
- Depth
- 78 km
- Intermediate
- 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
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
33 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: intermediate
78 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 M4.9 on July 16, 1974. 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 218 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 · 204 km S of this epicenter
- 7.5Kermadec Islands regionFebruary 27, 1955 · 143 km NE of this epicenter
- 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 142 km SW of this epicenter
- 7.3Kermadec Islands regionSeptember 14, 1959 · 92 km NW of this epicenter
- 7.3Kermadec Islands, New ZealandMarch 26, 1963 · 135 km SW of this epicenter
- 7.3Kermadec Islands, New ZealandJuly 25, 1968 · 226 km SW of this epicenter
- 7.2Kermadec Islands regionJuly 2, 1974 · 59 km NE of this epicenter
- 7.2Kermadec Islands, New ZealandAugust 2, 1941 · 118 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 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 · 245 km away
Limited damage (under $1M)tsunami
- 1917M8.0
Kermadec Islands
1 May 1917 · 54 km away
tsunami
- 1955M7.8
Kermadec Islands
27 Feb 1955 · 179 km away
- 1959M7.7
Kermadec Islands
14 Sep 1959 · 109 km away
- 1943M7.6
S Of
14 Sep 1943 · 87 km away
- 1917M7.5
S Of
16 Nov 1917 · 107 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.