Reviewed by USGSVanuatu41y ago
M5.5 earthquake 254 km SSE of Isangel, Vanuatu
Monday, February 10, 1986, 09:51:12 UTC · 21.585°S, 170.404°E
A magnitude 5.5 earthquake struck 254 km SSE of Isangel, Vanuatu on Monday, February 10, 1986, 09:51:12 UTC, at a depth of 100.7 km (intermediate). It is the strongest earthquake within 300 km since an M7.1 on January 15, 1986.
- Magnitude
- 5.5
- Moderate · mw
- Depth
- 101 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
3 kilotons of TNT
That is about 1/6 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.
Tectonic setting
100 km
from the nearest mapped plate boundary, between the New Hebrides and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
101 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 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.8 on March 6, 1986. 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 537 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11920 Vanuatu EarthquakeSeptember 20, 1920 · 268 km NW of this epicenter
- 7.828 km ESE of Isangel, VanuatuJune 16, 1910 · 238 km N of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 86 km S of this epicenter
- 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 164 km SE of this epicenter
- 7.262 km NE of Isangel, VanuatuJuly 2, 1953 · 289 km N of this epicenter
- 7.2207 km E of Tadine, New CaledoniaOctober 25, 1980 · 66 km SW of this epicenter
- 7.1southeast of the Loyalty IslandsAugust 17, 1935 · 136 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 26 recorded deaths. The most severe:
- 1875M8.1
Loyalty Islands: Lifou Island
28 Mar 1875 · 265 km away
26 deathsSevere damage ($5–24M)tsunami
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 62 km away
Moderate damage ($1–5M)tsunami
- 1920M8.1
Loyalty Islands
20 Sep 1920 · 268 km away
Limited damage (under $1M)tsunami
- 1913M8.1
Vanuatu Islands
14 Oct 1913 · 274 km away
- 1910M7.5
Vanuatu Islands
1 Jun 1910 · 229 km away
- 1928M7.5
Loyalty Islands
16 Mar 1928 · 47 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.