Reviewed by USGS42y ago
M7.1 earthquake southeast of the Loyalty Islands
Thursday, November 15, 1984, 02:46:19 UTC · 22.022°S, 170.950°E
A magnitude 7.1 earthquake struck southeast of the Loyalty Islands on Thursday, November 15, 1984, 02:46:19 UTC, at a depth of 104.7 km (intermediate). It is the strongest earthquake within 300 km since an M7.2 on October 25, 1980.
- Magnitude
- 7.1
- Major · mw
- Depth
- 105 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 earthquakeDashed circle: 200 km aftershock search area
In context
How big was it, and why here?
Energy released
674 kilotons of TNT
That is about 45 times the Hiroshima bomb. It released about 1,413 times the energy of a magnitude 5.0.
Tectonic setting
98 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
105 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 200 km
USGS lists 7 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.0 on December 10, 1984. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.5southeast of the Loyalty Islands42y ago · 138 km SE of this epicenter
- 5.0southeast of the Loyalty Islands42y ago · 19 km W of this epicenter
- 4.5284 km ESE of Tadine, New Caledonia42y ago · 52 km SW of this epicenter
- 4.7205 km SE of Isangel, Vanuatu42y ago · 153 km N of this epicenter
- 5.0southeast of the Loyalty Islands42y ago · 147 km SE of this epicenter
- 4.3southeast of the Loyalty Islands42y ago · 64 km SE of this epicenter
- 4.5southeast of the Loyalty Islands42y ago · 168 km SE of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 458 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 68 km SW of this epicenter
- 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 89 km SE of this epicenter
- 7.2207 km E of Tadine, New CaledoniaOctober 25, 1980 · 114 km W of this epicenter
- 7.1southeast of the Loyalty IslandsAugust 17, 1935 · 62 km SE of this epicenter
- 7.1southeast of the Loyalty IslandsApril 14, 1906 · 49 km SE of this epicenter
- 7.1175 km SE of Isangel, VanuatuMarch 30, 1910 · 154 km N of this epicenter
- 7.191 km SSE of Isangel, VanuatuMay 26, 1950 · 234 km NW 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:
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 98 km away
Moderate damage ($1–5M)tsunami
- 1928M7.5
Loyalty Islands
16 Mar 1928 · 46 km away
- 1943M7.5
Loyalty Islands
14 Sep 1943 · 6 km away
- 1944M7.5
Loyalty Islands
5 Oct 1944 · 120 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.