Reviewed by USGS96y ago
M6.7 earthquake southeast of the Loyalty Islands
Monday, March 2, 1931, 02:18:30 UTC · 21.948°S, 170.798°E
A magnitude 6.7 earthquake struck southeast of the Loyalty Islands on Monday, March 2, 1931, 02:18:30 UTC, at a depth of 70.0 km (intermediate). It is the strongest earthquake within 300 km since an M6.7 on November 6, 1928.
- Magnitude
- 6.7
- Strong · mw
- Depth
- 70 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 earthquake
In context
How big was it, and why here?
Energy released
163 kilotons of TNT
That is about 11 times the Hiroshima bomb. It released about 343 times the energy of a magnitude 5.0.
Tectonic setting
97 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: intermediate
70 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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 41 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.828 km ESE of Isangel, VanuatuJune 16, 1910 · 292 km NW of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 62 km SW of this epicenter
- 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 107 km SE of this epicenter
- 7.1southeast of the Loyalty IslandsApril 14, 1906 · 66 km SE of this epicenter
- 7.1175 km SE of Isangel, VanuatuMarch 30, 1910 · 141 km N of this epicenter
- 7.0southeast of the Loyalty IslandsAugust 25, 1926 · 194 km SE of this epicenter
- 7.0204 km E of Tadine, New CaledoniaFebruary 1, 1923 · 103 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 3 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 82 km away
Moderate damage ($1–5M)tsunami
- 1910M7.5
Vanuatu Islands
1 Jun 1910 · 286 km away
- 1928M7.5
Loyalty Islands
16 Mar 1928 · 31 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.