Reviewed by USGS5y ago
M4.1 earthquake in Vanuatu region
Saturday, October 2, 2021, 11:01:19 UTC · 21.244°S, 174.447°E
A magnitude 4.1 earthquake struck in Vanuatu region on Saturday, October 2, 2021, 11:01:19 UTC, at a depth of 516.7 km (deep).
- Magnitude
- 4.1
- Light · mb
- Depth
- 517 km
- Deep
- 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
21 tons of TNT
That is about 1/707 of the Hiroshima bomb. A magnitude 5.0 releases about 22 times more energy.
Tectonic setting
34 km
from the nearest mapped plate boundary, between the Conway Reef and New Hebrides plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: deep
517 km
Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.
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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M6.9 on October 9, 2021. 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 258 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.6south of the Fiji IslandsMarch 3, 1990 · 122 km SE of this epicenter
- 7.3Vanuatu regionOctober 2, 2021 · 48 km E of this epicenter
- 7.2southeast of the Loyalty IslandsAugust 12, 2016 · 194 km SW of this epicenter
- 7.1Vanuatu regionFebruary 25, 2000 · 202 km N of this epicenter
- 7.0southeast of the Loyalty IslandsOctober 5, 1944 · 295 km W of this epicenter
- 6.9225 km SW of Nadi, FijiJanuary 3, 2017 · 267 km NE of this epicenter
- 6.8south of the Fiji IslandsNovember 7, 1988 · 125 km SE of this epicenter
- 6.8southeast of the Loyalty IslandsMarch 10, 1906 · 293 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 4 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1990M7.6
Fiji Islands
3 Mar 1990 · 122 km away
- 1944M7.5
Loyalty Islands
5 Oct 1944 · 288 km away
- 2016M7.2
Loyalty Islands
12 Aug 2016 · 194 km away · intensity VI
tsunami
- 2017M6.9
Fiji Islands
3 Jan 2017 · 267 km away · intensity VI
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.