Reviewed by USGSIndonesia56y ago
M5.6 earthquake 139 km WSW of Abepura, Indonesia
Monday, January 18, 1971, 11:24:57 UTC · 2.880°S, 139.414°E
A magnitude 5.6 earthquake struck 139 km WSW of Abepura, Indonesia on Monday, January 18, 1971, 11:24:57 UTC, at a depth of 30.0 km (shallow). It is the strongest earthquake within 300 km since an M5.8 on January 14, 1971.
- Magnitude
- 5.6
- Moderate · mw
- Depth
- 30 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
4 kilotons of TNT
That is about 1/3 of the Hiroshima bomb. It released about 9 times the energy of a magnitude 5.0.
Tectonic setting
20 km
from the nearest mapped plate boundary, between the Woodlark and Maoke plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
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 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.5 on January 29, 1971. 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 106 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21914 Biak EarthquakeMay 26, 1914 · 292 km W of this epicenter
- 7.8230 km W of Abepura, IndonesiaJune 1, 1906 · 104 km NW of this epicenter
- 7.8New Guinea, Papua New GuineaSeptember 20, 1935 · 244 km SE of this epicenter
- 7.7120 km SW of Abepura, IndonesiaJanuary 10, 1971 · 51 km SE of this epicenter
- 7.6158 km WSW of Abepura, IndonesiaOctober 26, 1926 · 19 km W of this epicenter
- 7.5143 km WSW of Abepura, IndonesiaMay 28, 1968 · 5 km W of this epicenter
- 7.593 km SW of Aitape, Papua New GuineaJuly 29, 1917 · 273 km E of this epicenter
- 7.3195 km E of Biak, IndonesiaApril 2, 1947 · 264 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 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 · 140 km away
5 deathsLimited damage (under $1M)tsunami
- 1914M8.1
New Guinea: Irian Jaya: Japen
26 May 1914 · 298 km away · intensity IX
Moderate damage ($1–5M)tsunami
- 1971M8.1
New Guinea: Irian Jaya:Djajapura,Sentani
10 Jan 1971 · 40 km away · intensity IX
Moderate damage ($1–5M)
- 1921
New Guinea: Irian Jaya: Sentani
10 Oct 1921 · 94 km away · intensity VII
Moderate damage ($1–5M)
- 1919
Irian Jaya Region
21 Nov 1919 · 153 km away · intensity VIII
Limited damage (under $1M)tsunami
- 1926M7.9
New Guinea: Irian Jaya
26 Oct 1926 · 123 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.