M7.2 earthquake southeast of the Loyalty Islands

Friday, August 12, 2016, 01:26:36 UTC · 22.477°S, 173.117°E

A magnitude 7.2 earthquake struck southeast of the Loyalty Islands on Friday, August 12, 2016, 01:26:36 UTC, at a depth of 16.4 km (shallow). USGS received 2 “Did You Feel It?” reports, with a maximum reported intensity of VI (strong). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M7.5 on January 4, 1998.

Tsunami flagUSGS sets this flag for large events in oceanic regions so tsunami warning centers review them. It does not by itself mean a tsunami occurred. Check tsunami.gov and local authorities for official messages.

Magnitude: 7.2; Major · mww
Depth: 16 km; Shallow
Felt reports: 2; Max intensity VI
Est. shaking: V; Moderate (ShakeMap)
PAGER alert: Green; Impact estimate
Tsunami: Flag; Check tsunami.gov

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

In context

How big was it, and why here?

Energy released

951 kilotons of TNT

That is about 63 times the Hiroshima bomb. It released about 1,995 times the energy of a magnitude 5.0.

Tectonic setting

40 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

16 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
Nouméa, Sud, New Caledonia	VI · Strong	1	687 km
Namosi, Central, Fiji Islands	II · Weak	1	719 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 populated area was estimated to feel noticeable shaking.

After the main event

Aftershocks within 200 km

USGS lists 78 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.5 on August 20, 2016. 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 549 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 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

1990M7.6
Fiji Islands
3 Mar 1990 · 214 km away
1928M7.5
Loyalty Islands
16 Mar 1928 · 274 km away
1943M7.5
Loyalty Islands
14 Sep 1943 · 224 km away
1944M7.5
Loyalty Islands
5 Oct 1944 · 115 km away
2016M7.2
Loyalty Islands
12 Aug 2016 · 0 km away · intensity VI
tsunami
2012M6.6
Loyalty Islands
3 Mar 2012 · 288 km away
tsunami

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

Nearby trackers