QuakeScout
Magnitude5.9

Reviewed by USGS23y ago

M5.9 earthquake in Fiji region

Thursday, August 14, 2003, 18:23:06 UTC · 19.899°S, 177.984°W

A magnitude 5.9 earthquake struck in Fiji region on Thursday, August 14, 2003, 18:23:06 UTC, at a depth of 563.3 km (deep). It is the strongest earthquake within 300 km since an M6.6 on July 27, 2003.

Magnitude
5.9
Moderate · mwc
Depth
563 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: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

11 kilotons of TNT

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

Tectonic setting

168 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

563 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 75 km

USGS lists 5 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.3 on August 18, 2003. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M61h6h1d3d7d14d30dMainshock M5.9
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.2Fiji region23y ago · 58 km SW of this epicenter
  2. 4.0Fiji region23y ago · 45 km N of this epicenter
  3. 4.1295 km WNW of Haveluloto, Tonga23y ago · 38 km S of this epicenter
  4. 4.3276 km WNW of Haveluloto, Tonga23y ago · 45 km SE of this epicenter
  5. 3.8Fiji region23y ago · 72 km N of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,395 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.8159 km W of Pangai, TongaDecember 14, 1950 · 222 km E of this epicenter
  2. 7.8Fiji regionJanuary 1, 1919 · 65 km N of this epicenter
  3. 7.8192 km WSW of Haveluloto, TongaOctober 14, 1997 · 275 km SE of this epicenter
  4. 7.7Fiji regionAugust 19, 2002 · 255 km SW of this epicenter
  5. 7.6178 km E of Levuka, FijiFebruary 22, 1909 · 218 km NW of this epicenter
  6. 7.6240 km E of Levuka, FijiMarch 9, 1994 · 212 km N of this epicenter
  7. 7.5262 km WNW of Haveluloto, TongaMay 21, 1962 · 59 km E of this epicenter
  8. 7.4227 km E of Levuka, FijiAugust 21, 1910 · 239 km N of this epicenter

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:

  1. 1937M8.1

    Fiji Islands

    16 Apr 1937 · 205 km away

  2. 1909M7.8

    Fiji Islands

    22 Feb 1909 · 237 km away

  3. 1919M7.8

    Fiji Islands

    1 Jan 1919 · 65 km away

    tsunami

  4. 1950M7.7

    Tonga Islands

    14 Dec 1950 · 212 km away · intensity VI

  5. 1997M7.7

    Tonga Islands

    14 Oct 1997 · 275 km away

    tsunami

  6. 2002M7.7

    Fiji Islands

    19 Aug 2002 · 255 km away

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

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