M7.8 earthquake in New Guinea, Papua New Guinea

Friday, September 20, 1935, 01:46:43 UTC · 3.868°S, 141.379°E

A magnitude 7.8 earthquake struck in New Guinea, Papua New Guinea on Friday, September 20, 1935, 01:46:43 UTC, at a depth of 30.0 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: 30 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

8.4 megatons of TNT

That is about 557 times the Hiroshima bomb. It released about 17,579 times the energy of a magnitude 5.0.

Tectonic setting

115 km

from the nearest mapped plate boundary, between the Woodlark and Maoke plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

30 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 4 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M7.0 on September 20, 1935. 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 32 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 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5 recorded deaths. The most severe:

1900M6.9
Nw. Irian Jaya
7 Oct 1900 · 154 km away
5 deathsLimited damage (under $1M)tsunami
1907M7.4
Bismarck Sea
15 Dec 1907 · 151 km away
Moderate damage ($1–5M)tsunami
1919
Irian Jaya Region
21 Nov 1919 · 162 km away · intensity VIII
Limited damage (under $1M)tsunami
1935M7.8
N-Central
20 Sep 1935 · 6 km away
tsunami
1917M7.5
Papua New Guinea
29 Jul 1917 · 43 km away
tsunami
1918M7.5
N Coast
3 Jul 1918 · 131 km away

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

Nearby trackers