M7.3 earthquake 33 km NW of Port-Vila, Vanuatu

Tuesday, August 10, 2010, 05:23:44 UTC · 17.541°S, 168.069°E

A magnitude 7.3 earthquake struck 33 km NW of Port-Vila, Vanuatu on Tuesday, August 10, 2010, 05:23:44 UTC, at a depth of 25.0 km (shallow). USGS received 45 “Did You Feel It?” reports, with a maximum reported intensity of VII (very strong). It is the strongest earthquake within 300 km since an M7.3 on April 9, 2008.

Magnitude: 7.3; Major · mwc
Depth: 25 km; Shallow
Felt reports: 45; Max intensity VII
Est. shaking: VII; Very strong (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

87 km

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

Depth: shallow

25 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

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
Vila, Shefa, Vanuatu	VII · Very strong	29	42 km
Luganville, Sanma, Vanuatu	III · Weak	2	246 km
Longana, Penama, Vanuatu	VI · Strong	1	249 km
Nouméa, Sud, New Caledonia	II · Weak	1	551 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 109 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.9 on August 11, 2010. 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 1,239 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 44 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 37 recorded deaths. The most severe:

1875M8.1
Loyalty Islands: Lifou Island
28 Mar 1875 · 277 km away
26 deathsSevere damage ($5–24M)tsunami
1999M7.5
Pentecost
26 Nov 1999 · 125 km away
10 deathsSevere damage ($5–24M)tsunami
1971M7.1
Espiritu Santo, Port Vila
27 Oct 1971 · 245 km away · intensity VII
1 deathSevere damage ($5–24M)
1965M7.6
Vanuatu Islands
11 Aug 1965 · 215 km away
Moderate damage ($1–5M)tsunami
1973M7.2
Luganville, Lamap
29 Dec 1973 · 297 km away · intensity VIII
Moderate damage ($1–5M)
1990M6.4
Espiritu Santo
27 Jul 1990 · 251 km away · intensity V
Moderate damage ($1–5M)

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

Nearby trackers