M4.2 earthquake in Fiji region

Tuesday, October 9, 2018, 08:24:11 UTC · 18.517°S, 177.851°W

A magnitude 4.2 earthquake struck in Fiji region on Tuesday, October 9, 2018, 08:24:11 UTC, at a depth of 562.1 km (deep).

Magnitude: 4.2; Light · mb
Depth: 562 km; Deep
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

30 tons of TNT

That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.

Tectonic setting

137 km

from the nearest mapped plate boundary, between the Niuafo'ou and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: deep

562 km

Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.

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 12 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.5 on November 4, 2018. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,693 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 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

1979M6.9
Fiji Islands
16 Nov 1979 · 299 km away
Moderate damage ($1–5M)tsunami
1932M6.4
Koro,Mudu,Suvasavu
8 Mar 1932 · 255 km away · intensity VII
Moderate damage ($1–5M)
2018M8.2
Fiji Islands
19 Aug 2018 · 55 km away · intensity V
tsunami
2018M7.9
Fiji Islands
6 Sep 2018 · 295 km away · intensity VII
1909M7.8
Fiji Islands
22 Feb 1909 · 134 km away
1919M7.8
Fiji Islands
1 Jan 1919 · 92 km away
tsunami

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

Nearby trackers