M4.9 earthquake 200 km NW of Kiunga, Papua New Guinea

Sunday, July 18, 1976, 18:23:16 UTC · 4.929°S, 139.930°E

A magnitude 4.9 earthquake struck 200 km NW of Kiunga, Papua New Guinea on Sunday, July 18, 1976, 18:23:16 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.9 on July 17, 1976.

Magnitude: 4.9; Light · mb
Depth: 33 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

338 tons of TNT

That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.

Tectonic setting

12 km

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

Depth: shallow

33 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

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

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 50 km

USGS lists 9 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.6 on July 24, 1976. 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 115 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 10 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 6,138 recorded deaths. The most severe:

1976M7.1
New Guinea: Irian Jaya
25 Jun 1976 · 40 km away
6,000 deathsSevere damage ($5–24M)
1976M7.1
New Guinea: Irian Jaya: Jayawijaya
29 Oct 1976 · 46 km away · intensity VIII
133 deathsLimited damage (under $1M)
1900M6.9
Nw. Irian Jaya
7 Oct 1900 · 104 km away
5 deathsLimited damage (under $1M)tsunami
1971M8.1
New Guinea: Irian Jaya:Djajapura,Sentani
10 Jan 1971 · 205 km away · intensity IX
Moderate damage ($1–5M)
1919
Irian Jaya Region
21 Nov 1919 · 280 km away · intensity VIII
Limited damage (under $1M)tsunami
1926M7.9
New Guinea: Irian Jaya
26 Oct 1926 · 224 km away

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

Nearby trackers