M4.1 earthquake 29 km WSW of Finschhafen, Papua New Guinea

Monday, March 2, 1987, 23:35:08 UTC · 6.682°S, 147.610°E

A magnitude 4.1 earthquake struck 29 km WSW of Finschhafen, Papua New Guinea on Monday, March 2, 1987, 23:35:08 UTC, at a depth of 33.0 km (shallow).

Magnitude: 4.1; 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

21 tons of TNT

That is about 1/707 of the Hiroshima bomb. A magnitude 5.0 releases about 22 times more energy.

Tectonic setting

46 km

from the nearest mapped plate boundary, between the South Bismarck and Woodlark plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

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 13 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M6.0 on March 16, 1987. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 498 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 17 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 3 recorded deaths. The most severe:

1987M7.6
Huon Peninsula, Umboi Island
8 Feb 1987 · 67 km away · intensity VII
3 deaths$3 million damagetsunami
1906M8.0
New Britain
14 Sep 1906 · 157 km away
Severe damage ($5–24M)tsunami
1857M8.0
Bismarck Sea
17 Apr 1857 · 148 km away
Moderate damage ($1–5M)tsunami
1873M8.0
Maclay Coast
1873 · 221 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
1979M6.2
E, Mt Hagen
25 Jun 1979 · 294 km away
Moderate damage ($1–5M)

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers