Reviewed by USGSPapua New Guinea109y ago
M7.6 earthquake 50 km N of Wewak, Papua New Guinea
Wednesday, July 3, 1918, 06:52:08 UTC · 3.094°S, 143.573°E
A magnitude 7.6 earthquake struck 50 km N of Wewak, Papua New Guinea on Wednesday, July 3, 1918, 06:52:08 UTC, at a depth of 15.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.6
- Major · mw
- Depth
- 15 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
3.5 megatons of TNT
That is about 235 times the Hiroshima bomb. It released about 7,413 times the energy of a magnitude 5.0.
Tectonic setting
10 km
from the nearest mapped plate boundary, between the North Bismarck and Woodlark plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
15 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 M6.7 on July 29, 1918. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 7 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.593 km SW of Aitape, Papua New GuineaJuly 29, 1917 · 216 km W of this epicenter
- 7.349 km NNE of Angoram, Papua New GuineaMay 7, 1907 · 96 km SE of this epicenter
- 7.1132 km NNE of Wewak, Papua New GuineaAugust 26, 1906 · 96 km NE of this epicenter
- 7.165 km ENE of Wewak, Papua New GuineaApril 27, 1909 · 71 km E of this epicenter
- 7.073 km ENE of Vanimo, Papua New GuineaDecember 15, 1907 · 201 km NW of this epicenter
- 6.887 km NNE of Wewak, Papua New GuineaJune 4, 1913 · 56 km NE of this epicenter
- 6.680 km WNW of Porgera, Papua New GuineaJuly 29, 1910 · 275 km SW of this epicenter
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. The most severe:
- 1907M7.4
Bismarck Sea
15 Dec 1907 · 119 km away
Moderate damage ($1–5M)tsunami
- 1916M7.5
N Coast
3 Aug 1916 · 144 km away
- 1917M7.5
Papua New Guinea
29 Jul 1917 · 216 km away
tsunami
- 1918M7.5
N Coast
3 Jul 1918 · 127 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.