Reviewed by USGSPapua New Guinea40y ago
M4.9 earthquake 120 km N of Finschhafen, Papua New Guinea
Monday, March 23, 1987, 10:09:45 UTC · 5.471°S, 147.781°E
A magnitude 4.9 earthquake struck 120 km N of Finschhafen, Papua New Guinea on Monday, March 23, 1987, 10:09:45 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.0 on March 23, 1987.
- Magnitude
- 4.9
- Light · mb
- Depth
- 33 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
338 tons of TNT
That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.
Tectonic setting
165 km
from the nearest mapped plate boundary, between the South Bismarck and Woodlark plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
33 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.7 on March 24, 1987. 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 603 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.01906 Papua New Guinea EarthquakeSeptember 14, 1906 · 107 km SW of this epicenter
- 7.638 km NW of Finschhafen, Papua New GuineaOctober 2, 1906 · 97 km S of this epicenter
- 7.548 km NW of Finschhafen, Papua New GuineaMay 12, 1938 · 87 km S of this epicenter
- 7.549 km WSW of Wau, Papua New GuineaFebruary 26, 1963 · 280 km SW of this epicenter
- 7.532 km SSW of Kimbe, Papua New GuineaDecember 28, 1945 · 253 km E of this epicenter
- 7.492 km WSW of Kandrian, Papua New GuineaMay 6, 1947 · 156 km SE of this epicenter
- 7.4177 km SW of Kavieng, Papua New GuineaJanuary 13, 1905 · 287 km NE of this epicenter
- 7.454 km NNW of Finschhafen, Papua New GuineaFebruary 8, 1987 · 69 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 22 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 21 recorded deaths. The most severe:
- 1970M7.3
Madang
31 Oct 1970 · 263 km away · intensity VIII
18 deaths$2 million damagetsunami
- 1987M7.6
Huon Peninsula, Umboi Island
8 Feb 1987 · 69 km away · intensity VII
3 deaths$3 million damagetsunami
- 1906M8.0
New Britain
14 Sep 1906 · 217 km away
Severe damage ($5–24M)tsunami
- 1857M8.0
Bismarck Sea
17 Apr 1857 · 87 km away
Moderate damage ($1–5M)tsunami
- 1873M8.0
Maclay Coast
1873 · 197 km away · intensity IX
Moderate damage ($1–5M)tsunami
- 1987M7.7
New Britain: Kandrian, Kimbte
16 Oct 1987 · 167 km away · intensity VIII
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.