M7.9 earthquake 35 km WNW of Panguna, Papua New Guinea

Sunday, January 22, 2017, 04:30:22 UTC · 6.246°S, 155.172°E

A magnitude 7.9 earthquake struck 35 km WNW of Panguna, Papua New Guinea on Sunday, January 22, 2017, 04:30:22 UTC, at a depth of 135.0 km (intermediate). USGS received 30 “Did You Feel It?” reports, with a maximum reported intensity of IX (violent). The USGS PAGER alert is yellow: some casualties and damage are possible. It is the strongest earthquake within 300 km since an M7.9 on December 17, 2016.

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: 7.9; Major · mww
Depth: 135 km; Intermediate
Felt reports: 30; Max intensity IX
Est. shaking: VII; Very strong (ShakeMap)
PAGER alert: Yellow; Impact estimate
Tsunami: Flag; Check tsunami.gov

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

11 megatons of TNT

That is about 709 times the Hiroshima bomb. It released about 22,387 times the energy of a magnitude 5.0.

Tectonic setting

71 km

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

Depth: intermediate

135 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
Panguna, North Solomons, Papua New Guinea	IX · Violent	7	139 km
Kokopo, East New Britain, Papua New Guinea	VI · Strong	4	407 km
Namatanai, New Ireland, Papua New Guinea	III · Weak	4	437 km
Arawa, North Solomons, Papua New Guinea	VIII · Severe	2	141 km
Lae, Morobe, Papua New Guinea	II · Weak	2	916 km
Buin, North Solomons, Papua New Guinea	VII · Very strong	1	161 km
Kieta, North Solomons, Papua New Guinea	VI · Strong	1	143 km
Gizo, Western, Solomon Islands	V · Moderate	1	307 km
Kimbe, West New Britain, Papua New Guinea	IV · Light	1	578 km
Wewak, East Sepik, Papua New Guinea	III · Weak	1	1322 km
Honiara, Guadalcanal, Solomon Islands	II · Weak	1	644 km
Bulolo, Morobe, Papua New Guinea	II · Weak	1	957 km

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

Modelled from the ShakeMap and population data. Alert level yellow: some casualties and damage are possible.

VIII · Severe shaking: 88,000 people
VII · Very strong shaking: 146,000 people
VI · Strong shaking: 28,000 people
V · Moderate shaking: 157,000 people
IV · Light shaking: 555,000 people
III · Weak shaking: 230,000 people

After the main event

Aftershocks within 200 km

USGS lists 31 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.6 on January 22, 2017. 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 2,003 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 32 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 13 recorded deaths. The most severe:

1939M7.7
Bougainville Island
30 Jan 1939 · 96 km away
5 deathsModerate damage ($1–5M)tsunami
1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 163 km away · intensity IX
3 deathsUnder $1 million damagetsunami
2017M7.9
Bougainville Island
22 Jan 2017 · 0 km away · intensity IX
3 deathsLimited damage (under $1M)tsunami
1996M7.2
Bougainville Island
29 Apr 1996 · 36 km away
1 deathModerate damage ($1–5M)
2014M7.1
Bougainville Island
11 Apr 2014 · 40 km away
1 deathLimited damage (under $1M)
1975M7.9
Bismarck Sea: Bougainville
20 Jul 1975 · 40 km away · intensity VIII
Severe damage ($5–24M)tsunami

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

Nearby trackers