Reviewed by USGSPapua New Guinea44y ago
M4.7 earthquake 199 km SE of Kokopo, Papua New Guinea
Wednesday, April 6, 1983, 10:30:35 UTC · 5.553°S, 153.601°E
A magnitude 4.7 earthquake struck 199 km SE of Kokopo, Papua New Guinea on Wednesday, April 6, 1983, 10:30:35 UTC, at a depth of 53.7 km (shallow). It is the strongest earthquake within 300 km since an M4.7 on April 3, 1983.
- Magnitude
- 4.7
- Light · mb
- Depth
- 54 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
169 tons of TNT
That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.
Tectonic setting
8 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
54 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 50 km
USGS lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.4 on April 12, 1983. 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 945 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 · 88 km N of this epicenter
- 8.11971 Bougainville EarthquakeJuly 26, 1971 · 89 km NW of this epicenter
- 8.01971 New Britain EarthquakeJuly 14, 1971 · 31 km E of this epicenter
- 8.060 km SE of Kokopo, Papua New GuineaJanuary 1, 1916 · 140 km NW of this epicenter
- 7.956 km WSW of Panguna, Papua New GuineaJuly 20, 1975 · 198 km SE of this epicenter
- 7.885 km S of Panguna, Papua New GuineaJanuary 30, 1939 · 261 km SE of this epicenter
- 7.874 km SSW of Kokopo, Papua New GuineaFebruary 2, 1920 · 187 km W of this epicenter
- 7.794 km SSW of Panguna, Papua New GuineaJuly 20, 1975 · 243 km SE 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 530 recorded deaths. The most severe:
- 1937
Keravia, Rabaul, Kokopo
28 May 1937 · 210 km away · intensity VIII
507 deathsLimited damage (under $1M)tsunami
- 1983M6.4
Ulawun, Rabaul
22 Dec 1983 · 193 km away · intensity V
10 deaths$25 million damage
- 1939M7.7
Bougainville Island
30 Jan 1939 · 260 km away
5 deathsModerate damage ($1–5M)tsunami
- 1941M7.4
Bismarck Sea
13 Jan 1941 · 229 km away
4 deathsModerate damage ($1–5M)tsunami
- 1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 34 km away · intensity IX
3 deathsUnder $1 million damagetsunami
- 1878
Bismarck Sea
4 Feb 1878 · 208 km away
1 deathtsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.