Reviewed by USGS5y ago
M5.4 earthquake southeast of the Loyalty Islands
Tuesday, July 13, 2021, 11:26:50 UTC · 23.317°S, 172.302°E
A magnitude 5.4 earthquake struck southeast of the Loyalty Islands on Tuesday, July 13, 2021, 11:26:50 UTC, at a depth of 10.0 km (shallow). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M5.5 on June 23, 2021.
- Magnitude
- 5.4
- Moderate · mww
- Depth
- 10 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- Green
- Impact estimate
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
2 kilotons of TNT
That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.
Tectonic setting
16 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 populated area was estimated to feel noticeable shaking.
After the main event
Aftershocks within 75 km
USGS lists 5 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.2 on July 18, 2021. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6southeast of the Loyalty Islands5y ago · 61 km N of this epicenter
- 4.3southeast of the Loyalty Islands5y ago · 62 km W of this epicenter
- 5.2southeast of the Loyalty Islands5y ago · 21 km NE of this epicenter
- 4.4southeast of the Loyalty Islands5y ago · 22 km NW of this epicenter
- 4.7southeast of the Loyalty Islands5y ago · 34 km N of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 873 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 · 72 km NW of this epicenter
- 7.7249 km E of Vao, New CaledoniaMay 16, 1995 · 248 km W of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 222 km NW of this epicenter
- 7.5southeast of the Loyalty IslandsJanuary 4, 1998 · 182 km NW of this epicenter
- 7.3201 km ESE of Tadine, New CaledoniaDecember 27, 2003 · 298 km NW of this epicenter
- 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 112 km NW of this epicenter
- 7.2207 km E of Tadine, New CaledoniaOctober 25, 1980 · 297 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 278 km away
Moderate damage ($1–5M)tsunami
- 1995M7.7
Noumea; Vanuatu: Port-Vila
16 May 1995 · 248 km away · intensity III
tsunami
- 2021M7.7
Loyalty Islands
10 Feb 2021 · 77 km away · intensity VII
tsunami
- 1928M7.5
Loyalty Islands
16 Mar 1928 · 236 km away
- 1943M7.5
Loyalty Islands
14 Sep 1943 · 198 km away
- 1944M7.5
Loyalty Islands
5 Oct 1944 · 96 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.