M7.1 earthquake 119 km S of Isangel, Vanuatu

Sunday, March 25, 2007, 00:40:01 UTC · 20.617°S, 169.357°E

A magnitude 7.1 earthquake struck 119 km S of Isangel, Vanuatu on Sunday, March 25, 2007, 00:40:01 UTC, at a depth of 34.0 km (shallow). USGS received 11 “Did You Feel It?” reports, with a maximum reported intensity of III (weak). It is the strongest earthquake within 300 km since an M7.1 on January 3, 2004.

Magnitude: 7.1; Major · mwb
Depth: 34 km; Shallow
Felt reports: 11; Max intensity III
Est. shaking: VI; 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

674 kilotons of TNT

That is about 45 times the Hiroshima bomb. It released about 1,413 times the energy of a magnitude 5.0.

Tectonic setting

80 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

34 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	III · Weak	5	338 km
Nouméa, Sud, New Caledonia	III · Weak	2	355 km
Yaté, Sud, New Caledonia	III · Weak	1	308 km
Mont-Doré, Sud, New Caledonia	II · Weak	1	343 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 65 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.9 on March 25, 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 1,125 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 25 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 26 recorded deaths. The most severe:

1875M8.1
Loyalty Islands: Lifou Island
28 Mar 1875 · 113 km away
26 deathsSevere damage ($5–24M)tsunami
1901M7.9
Loyalty Islands
9 Aug 1901 · 168 km away
Moderate damage ($1–5M)tsunami
1920M8.1
Loyalty Islands
20 Sep 1920 · 116 km away
Limited damage (under $1M)tsunami
1878M7.5
Tanna Island
10 Jan 1878 · 201 km away
Limited damage (under $1M)tsunami
1961M7.3
Vanuatu Islands
23 Jul 1961 · 264 km away · intensity VI
Limited damage (under $1M)tsunami
1913M8.1
Vanuatu Islands
14 Oct 1913 · 130 km away

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

Nearby trackers