Magnitude4.5

Reviewed by USGSVanuatu41y ago

M4.5 earthquake 275 km ESE of Isangel, Vanuatu

Monday, February 3, 1986, 00:53:07 UTC · 20.722°S, 171.604°E

A magnitude 4.5 earthquake struck 275 km ESE of Isangel, Vanuatu on Monday, February 3, 1986, 00:53:07 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.8 on January 24, 1986.

Magnitude
4.5
Light · mb
Depth
33 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

85 tons of TNT

That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.

Tectonic setting

185 km

from the nearest mapped plate boundary, between the Conway Reef and New Hebrides plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

33 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 50 km

USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 517 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 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1901M7.9

    Loyalty Islands

    9 Aug 1901 · 219 km away

    Moderate damage ($1–5M)tsunami

  2. 1910M7.9

    Vanuatu Islands

    16 Jun 1910 · 292 km away

  3. 1910M7.5

    Vanuatu Islands

    1 Jun 1910 · 283 km away

  4. 1928M7.5

    Loyalty Islands

    16 Mar 1928 · 182 km away

  5. 1943M7.5

    Loyalty Islands

    14 Sep 1943 · 155 km away

  6. 1944M7.5

    Loyalty Islands

    5 Oct 1944 · 202 km away

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

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