M7.8 earthquake south of the Fiji Islands

Sunday, December 9, 2007, 07:28:20 UTC · 25.996°S, 177.514°W

A magnitude 7.8 earthquake struck south of the Fiji Islands on Sunday, December 9, 2007, 07:28:20 UTC, at a depth of 152.5 km (intermediate). USGS received 28 “Did You Feel It?” reports, with a maximum reported intensity of VII (very strong). It is the strongest earthquake within 300 km since an M8.0 on January 14, 1976.

Magnitude: 7.8; Major · mwc
Depth: 153 km; Intermediate
Felt reports: 28; Max intensity VII
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search area

In context

How big was it, and why here?

Energy released

7.6 megatons of TNT

That is about 502 times the Hiroshima bomb. It released about 15,849 times the energy of a magnitude 5.0.

Tectonic setting

28 km

from the nearest mapped plate boundary, between the Kermadec and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: intermediate

153 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

Did You Feel It?

Where it was felt

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Nukuʿalofa, Tongatapu, Tonga	IV · Light	10	606 km
Lower Hutt, Wellington, New Zealand	II · Weak	3	1832 km
Vaini, Tongatapu, Tonga	VII · Very strong	2	600 km
Wellington, Wellington, New Zealand	III · Weak	2	1846 km
Napier, Hawkeʿs Bay, New Zealand	II · Weak	2	1592 km
Neiafu, Vavaʿu, Tonga	III · Weak	1	904 km
Pangai, Haʿapai, Tonga	III · Weak	1	772 km
Whakatane, Bay of Plenty, New Zealand	III · Weak	1	1433 km
Gold Coast, Queensland, Australia	II · Weak	1	2895 km
Muʿa, Tongatapu, Tonga	II · Weak	1	604 km
Alofi, _no region, Niue	II · Weak	1	1106 km

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 35 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.3 on December 13, 2007. 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 1,000 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:

1986M8.1
Raoul
20 Oct 1986 · 262 km away
Limited damage (under $1M)tsunami
1955M7.8
Kermadec Islands
27 Feb 1955 · 299 km away
1975M7.8
S Of Tonga
11 Oct 1975 · 270 km away
2007M7.8
Kermadec Islands
9 Dec 2007 · 0 km away
tsunami
1959M7.7
Kermadec Islands
14 Sep 1959 · 283 km away
1982M7.7
Tonga Trench
19 Dec 1982 · 266 km away
tsunami

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

Nearby trackers