Magnitude7.9

Reviewed by USGSVanuatu76y ago

M7.9 earthquake 99 km SW of Port-Vila, Vanuatu

Saturday, December 2, 1950, 19:51:51 UTC · 18.373°S, 167.654°E

A magnitude 7.9 earthquake struck 99 km SW of Port-Vila, Vanuatu on Saturday, December 2, 1950, 19:51:51 UTC, at a depth of 30.0 km (shallow). It is the strongest earthquake within 300 km since an M8.1 on September 20, 1920.

Magnitude
7.9
Major · mw
Depth
30 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
VI
Strong (ShakeMap)
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

11 megatons of TNT

That is about 709 times the Hiroshima bomb. It released about 22,387 times the energy of a magnitude 5.0.

Tectonic setting

20 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

30 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 200 km

USGS lists 2 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.2 on December 4, 1950. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M7M81h6h1d3d7d14d30dMainshock M7.9
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 6.277 km WSW of Port-Vila, Vanuatu76y ago · 48 km N of this epicenter
  2. 6.276 km W of Port-Vila, Vanuatu76y ago · 60 km N of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 65 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 20 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 26 recorded deaths. The most severe:

  1. 1875M8.1

    Loyalty Islands: Lifou Island

    28 Mar 1875 · 202 km away

    26 deathsSevere damage ($5–24M)tsunami

  2. 1920M8.1

    Loyalty Islands

    20 Sep 1920 · 199 km away

    Limited damage (under $1M)tsunami

  3. 1878M7.5

    Tanna Island

    10 Jan 1878 · 113 km away

    Limited damage (under $1M)tsunami

  4. 1933M6.4

    Malekula

    19 Nov 1933 · 165 km away

    Limited damage (under $1M)tsunami

  5. 1913M8.1

    Vanuatu Islands

    14 Oct 1913 · 189 km away

  6. 1878M8.0

    Vanuatu Islands

    11 Feb 1878 · 113 km away

    tsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers

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