QuakeScout
Magnitude3.5

Reviewed by USGS29y ago

M3.5 earthquake southeast of the Loyalty Islands

Monday, January 12, 1998, 07:55:29 UTC · 21.823°S, 171.187°E

A magnitude 3.5 earthquake struck southeast of the Loyalty Islands on Monday, January 12, 1998, 07:55:29 UTC, at a depth of 33.0 km (shallow).

Magnitude
3.5
Minor · 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 earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

3 tons of TNT

That is about 1/5,615 of the Hiroshima bomb. A magnitude 5.0 releases about 178 times more energy.

Tectonic setting

129 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: 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 lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M5.3 on February 1, 1998. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M3.5
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.3southeast of the Loyalty Islands29y ago · 48 km S of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 682 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.7249 km E of Vao, New CaledoniaMay 16, 1995 · 187 km SW of this epicenter
  2. 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 101 km SW of this epicenter
  3. 7.5southeast of the Loyalty IslandsJanuary 4, 1998 · 60 km SW of this epicenter
  4. 7.2southeast of the Loyalty IslandsNovember 14, 1906 · 91 km SE of this epicenter
  5. 7.2207 km E of Tadine, New CaledoniaOctober 25, 1980 · 138 km W of this epicenter
  6. 7.1southeast of the Loyalty IslandsAugust 17, 1935 · 61 km SE of this epicenter
  7. 7.1southeast of the Loyalty IslandsApril 14, 1906 · 54 km S of this epicenter

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 · 124 km away

    Moderate damage ($1–5M)tsunami

  2. 1995M7.7

    Noumea; Vanuatu: Port-Vila

    16 May 1995 · 187 km away · intensity III

    tsunami

  3. 1928M7.5

    Loyalty Islands

    16 Mar 1928 · 74 km away

  4. 1943M7.5

    Loyalty Islands

    14 Sep 1943 · 28 km away

  5. 1944M7.5

    Loyalty Islands

    5 Oct 1944 · 113 km away

  6. 1994M7.0

    Vanuatu Islands

    12 Feb 1994 · 236 km away

    tsunami

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

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