Magnitude7.3

Reviewed by USGSFiji17y ago

M7.3 earthquake 77 km ENE of Ba, Fiji

Monday, November 9, 2009, 10:44:55 UTC · 17.239°S, 178.331°E

A magnitude 7.3 earthquake struck 77 km ENE of Ba, Fiji on Monday, November 9, 2009, 10:44:55 UTC, at a depth of 595.0 km (deep). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.

Magnitude
7.3
Major · mwc
Depth
595 km
Deep
Felt reports
0
Did You Feel It?
Est. shaking
IV
Light (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

1.3 megatons of TNT

That is about 89 times the Hiroshima bomb. It released about 2,818 times the energy of a magnitude 5.0.

Tectonic setting

122 km

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

Depth: deep

595 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 200 km

USGS lists 3 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M4.9 on November 9, 2009. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M71h6h1d3d7d14d30dMainshock M7.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.776 km NE of Levuka, Fiji17y ago · 174 km E of this epicenter
  2. 4.585 km ENE of Ba, Fiji17y ago · 8 km E of this epicenter
  3. 4.990 km N of Suva, Fiji17y ago · 27 km E of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 271 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, which together caused about 48 recorded deaths. The most severe:

  1. 1840

    Kadavu

    1840 · 199 km away · intensity VIII

    40 deathsLimited damage (under $1M)

  2. 1953M6.4

    Fiji Islands

    14 Sep 1953 · 119 km away

    8 deathsLimited damage (under $1M)tsunami

  3. 1919M6.9

    Rabi,Tunuloa Mission,Suvasavu

    3 Oct 1919 · 201 km away · intensity VIII

    Moderate damage ($1–5M)

  4. 1979M6.9

    Fiji Islands

    16 Nov 1979 · 187 km away

    Moderate damage ($1–5M)tsunami

  5. 1932M6.4

    Koro,Mudu,Suvasavu

    8 Mar 1932 · 185 km away · intensity VII

    Moderate damage ($1–5M)

  6. 1884

    Macuata

    Jan 1884 · 155 km away · intensity VII

    Limited damage (under $1M)tsunami

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

Nearby trackers

Closest city pages