Reviewed by USGSPapua New Guinea41y ago
M4.6 earthquake 89 km SW of Kokopo, Papua New Guinea
Wednesday, December 25, 1985, 18:18:47 UTC · 4.987°S, 151.778°E
A magnitude 4.6 earthquake struck 89 km SW of Kokopo, Papua New Guinea on Wednesday, December 25, 1985, 18:18:47 UTC, at a depth of 126.0 km (intermediate). It is the strongest earthquake within 300 km since an M5.1 on December 18, 1985.
- Magnitude
- 4.6
- Light · mb
- Depth
- 126 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
99 km
from the nearest mapped plate boundary, between the South Bismarck and Solomon Sea plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
126 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 863 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21919 Papua New Guinea EarthquakeMay 6, 1919 · 231 km E of this epicenter
- 8.11971 Bougainville EarthquakeJuly 26, 1971 · 156 km E of this epicenter
- 8.01971 New Britain EarthquakeJuly 14, 1971 · 237 km E of this epicenter
- 8.060 km SE of Kokopo, Papua New GuineaJanuary 1, 1916 · 97 km E of this epicenter
- 7.874 km SSW of Kokopo, Papua New GuineaFebruary 2, 1920 · 27 km E of this epicenter
- 7.7152 km SE of Kokopo, Papua New GuineaSeptember 29, 1946 · 175 km E of this epicenter
- 7.6157 km ESE of Kokopo, Papua New GuineaMarch 18, 1983 · 200 km E of this epicenter
- 7.5199 km SSE of Kokopo, Papua New GuineaAugust 17, 1972 · 171 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 33 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 526 recorded deaths. The most severe:
- 1937
Keravia, Rabaul, Kokopo
28 May 1937 · 93 km away · intensity VIII
507 deathsLimited damage (under $1M)tsunami
- 1983M6.4
Ulawun, Rabaul
22 Dec 1983 · 46 km away · intensity V
10 deaths$25 million damage
- 1941M7.4
Bismarck Sea
13 Jan 1941 · 96 km away
4 deathsModerate damage ($1–5M)tsunami
- 1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 242 km away · intensity IX
3 deathsUnder $1 million damagetsunami
- 1985M7.1
New Britain: Bialla, Piona
10 May 1985 · 106 km away · intensity VIII
1 death$1 million damage
- 1878
Bismarck Sea
4 Feb 1878 · 97 km away
1 deathtsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.