Reviewed by USGS6y ago
M4.0 earthquake south of the Kermadec Islands
Friday, July 17, 2020, 17:49:24 UTC · 33.778°S, 178.668°W
A magnitude 4.0 earthquake struck south of the Kermadec Islands on Friday, July 17, 2020, 17:49:24 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 4.0
- Light · mb
- Depth
- 10 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
15 tons of TNT
That is about 1/998 of the Hiroshima bomb. A magnitude 5.0 releases about 32 times more energy.
Tectonic setting
43 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
10 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 M4.1 on August 8, 2020. 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 1,189 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.4south of the Kermadec IslandsJune 18, 2020 · 93 km NE of this epicenter
- 7.4Kermadec Islands regionMay 16, 2006 · 227 km N of this epicenter
- 7.1south of the Kermadec IslandsMay 25, 1997 · 234 km NW of this epicenter
- 6.9Kermadec Islands regionMay 3, 1997 · 231 km N of this epicenter
- 6.9south of the Kermadec IslandsSeptember 26, 1985 · 102 km S of this epicenter
- 6.9Kermadec Islands regionSeptember 10, 2018 · 236 km N of this epicenter
- 6.9south of the Kermadec IslandsJuly 11, 1943 · 141 km N of this epicenter
- 6.8south of the Kermadec IslandsFebruary 17, 1987 · 124 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 2020M7.4
S Of, Raoul
18 Jun 2020 · 93 km away · intensity VII
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.