Reviewed by USGS5y ago
M4.5 earthquake southeast of the Loyalty Islands
Sunday, May 16, 2021, 08:27:51 UTC · 23.066°S, 171.630°E
A magnitude 4.5 earthquake struck southeast of the Loyalty Islands on Sunday, May 16, 2021, 08:27:51 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M5.5 on May 15, 2021.
- Magnitude
- 4.5
- 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
85 tons of TNT
That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.
Tectonic setting
7 km
from the nearest mapped plate boundary, between the New Hebrides and Australian 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 6 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.2 on May 18, 2021. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.2southeast of the Loyalty Islands5y ago · 29 km N of this epicenter
- 4.0southeast of the Loyalty Islands5y ago · 34 km SW of this epicenter
- 4.9southeast of the Loyalty Islands5y ago · 22 km SE of this epicenter
- 4.5southeast of the Loyalty Islands5y ago · 30 km N of this epicenter
- 4.5southeast of the Loyalty Islands5y ago · 26 km NW of this epicenter
- 5.2southeast of the Loyalty Islands5y ago · 22 km S of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,108 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.7southeast of the Loyalty IslandsFebruary 10, 2021 · 3 km NE of this epicenter
- 7.7249 km E of Vao, New CaledoniaMay 16, 1995 · 177 km W of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 149 km NW of this epicenter
- 7.5southeast of the Loyalty IslandsJanuary 4, 1998 · 113 km NW of this epicenter
- 7.5166 km ESE of Tadine, New CaledoniaDecember 5, 2018 · 258 km NW of this epicenter
- 7.3201 km ESE of Tadine, New CaledoniaDecember 27, 2003 · 224 km NW of this epicenter
- 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 59 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 14 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 205 km away
Moderate damage ($1–5M)tsunami
- 2018M7.5
Loyalty Islands
5 Dec 2018 · 258 km away · intensity III
Limited damage (under $1M)tsunami
- 1995M7.7
Noumea; Vanuatu: Port-Vila
16 May 1995 · 177 km away · intensity III
tsunami
- 2021M7.7
Loyalty Islands
10 Feb 2021 · 3 km away · intensity VII
tsunami
- 1928M7.5
Loyalty Islands
16 Mar 1928 · 166 km away
- 1943M7.5
Loyalty Islands
14 Sep 1943 · 135 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.