Reviewed by USGSVanuatu46y ago
M5.1 earthquake 164 km S of Isangel, Vanuatu
Saturday, March 28, 1981, 20:33:30 UTC · 21.023°S, 169.450°E
A magnitude 5.1 earthquake struck 164 km S of Isangel, Vanuatu on Saturday, March 28, 1981, 20:33:30 UTC, at a depth of 48.5 km (shallow). It is the strongest earthquake within 300 km since an M5.2 on March 19, 1981.
- Magnitude
- 5.1
- Moderate · mb
- Depth
- 49 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 earthquake
In context
How big was it, and why here?
Energy released
674 tons of TNT
That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.
Tectonic setting
64 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
49 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 75 km
USGS has not published any M2.5+ earthquake within 75 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 457 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 · 154 km NW of this epicenter
- 7.828 km ESE of Isangel, VanuatuJune 16, 1910 · 158 km N of this epicenter
- 7.663 km NW of Isangel, VanuatuOctober 14, 1913 · 223 km N of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 178 km SE of this epicenter
- 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 280 km SE of this epicenter
- 7.247 km NNW of Isangel, VanuatuNovember 24, 1944 · 213 km N of this epicenter
- 7.262 km NE of Isangel, VanuatuJuly 2, 1953 · 216 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 17 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 · 151 km away
26 deathsSevere damage ($5–24M)tsunami
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 123 km away
Moderate damage ($1–5M)tsunami
- 1920M8.1
Loyalty Islands
20 Sep 1920 · 154 km away
Limited damage (under $1M)tsunami
- 1878M7.5
Tanna Island
10 Jan 1878 · 246 km away
Limited damage (under $1M)tsunami
- 1913M8.1
Vanuatu Islands
14 Oct 1913 · 176 km away
- 1878M8.0
Vanuatu Islands
11 Feb 1878 · 246 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.