Reviewed by USGSPapua New Guinea41y ago
M5.6 earthquake 69 km E of Kokopo, Papua New Guinea
Thursday, November 28, 1985, 14:54:42 UTC · 4.257°S, 152.887°E
A magnitude 5.6 earthquake struck 69 km E of Kokopo, Papua New Guinea on Thursday, November 28, 1985, 14:54:42 UTC, at a depth of 39.9 km (shallow). It is the strongest earthquake within 300 km since an M5.7 on October 28, 1985.
- Magnitude
- 5.6
- Moderate · mw
- Depth
- 40 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
4 kilotons of TNT
That is about 1/4 of the Hiroshima bomb. It released about 8 times the energy of a magnitude 5.0.
Tectonic setting
17 km
from the nearest mapped plate boundary, between the North Bismarck and South Bismarck plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
40 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 M4.9 on November 28, 1985. 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 830 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 · 124 km SE of this epicenter
- 8.11971 Bougainville EarthquakeJuly 26, 1971 · 75 km SE of this epicenter
- 8.01971 New Britain EarthquakeJuly 14, 1971 · 173 km SE of this epicenter
- 8.060 km SE of Kokopo, Papua New GuineaJanuary 1, 1916 · 63 km SW of this epicenter
- 7.874 km SSW of Kokopo, Papua New GuineaFebruary 2, 1920 · 125 km SW of this epicenter
- 7.7152 km SE of Kokopo, Papua New GuineaSeptember 29, 1946 · 117 km SE of this epicenter
- 7.6157 km ESE of Kokopo, Papua New GuineaMarch 18, 1983 · 104 km SE of this epicenter
- 7.5199 km SSE of Kokopo, Papua New GuineaAugust 17, 1972 · 198 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 31 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 · 76 km away · intensity VIII
507 deathsLimited damage (under $1M)tsunami
- 1983M6.4
Ulawun, Rabaul
22 Dec 1983 · 169 km away · intensity V
10 deaths$25 million damage
- 1941M7.4
Bismarck Sea
13 Jan 1941 · 91 km away
4 deathsModerate damage ($1–5M)tsunami
- 1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 178 km away · intensity IX
3 deathsUnder $1 million damagetsunami
- 1985M7.1
New Britain: Bialla, Piona
10 May 1985 · 253 km away · intensity VIII
1 death$1 million damage
- 1878
Bismarck Sea
4 Feb 1878 · 71 km away
1 deathtsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.