Magnitude7.8

Reviewed by USGSPapua New Guinea88y ago

M7.8 earthquake 85 km S of Panguna, Papua New Guinea

Monday, January 30, 1939, 02:18:30 UTC · 7.086°S, 155.388°E

A magnitude 7.8 earthquake struck 85 km S of Panguna, Papua New Guinea on Monday, January 30, 1939, 02:18:30 UTC, at a depth of 35.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.

Magnitude
7.8
Major · mw
Depth
35 km
Shallow
Felt reports
0
Did You Feel It?
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

8.1 megatons of TNT

That is about 538 times the Hiroshima bomb. It released about 16,982 times the energy of a magnitude 5.0.

Tectonic setting

39 km

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

Depth: shallow

35 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 200 km

USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.1 on February 2, 1939. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M7M81h6h1d3d7d14d30dMainshock M7.8
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 6.1162 km S of Panguna, Papua New Guinea88y ago · 77 km S of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 54 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 4 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5 recorded deaths. The most severe:

  1. 1939M7.7

    Bougainville Island

    30 Jan 1939 · 1 km away

    5 deathsModerate damage ($1–5M)tsunami

  2. 1907M7.7

    New Britain

    4 May 1907 · 192 km away

  3. 1913M7.5

    Solomon Islands

    30 May 1913 · 278 km away

  4. 1923M7.1

    Bismarck Archipelago

    2 Nov 1923 · 299 km away

    tsunami

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

Nearby trackers

Closest city pages