M5.5 earthquake 97 km ENE of Kainantu, Papua New Guinea

Thursday, March 5, 1987, 19:47:09 UTC · 5.887°S, 146.653°E

A magnitude 5.5 earthquake struck 97 km ENE of Kainantu, Papua New Guinea on Thursday, March 5, 1987, 19:47:09 UTC, at a depth of 56.0 km (shallow). It is the strongest earthquake within 300 km since an M5.5 on March 4, 1987.

Magnitude: 5.5; Moderate · mw
Depth: 56 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: IV; Light (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

3 kilotons of TNT

That is about 1/6 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.

Tectonic setting

64 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

56 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 4 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.0 on March 18, 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 526 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 18 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 · 170 km away · intensity VIII
18 deaths$2 million damagetsunami
1987M7.6
Huon Peninsula, Umboi Island
8 Feb 1987 · 117 km away · intensity VII
3 deaths$3 million damagetsunami
1906M8.0
New Britain
14 Sep 1906 · 287 km away
Severe damage ($5–24M)tsunami
1857M8.0
Bismarck Sea
17 Apr 1857 · 58 km away
Moderate damage ($1–5M)tsunami
1873M8.0
Maclay Coast
1873 · 84 km away · intensity IX
Moderate damage ($1–5M)tsunami
1987M7.7
New Britain: Kandrian, Kimbte
16 Oct 1987 · 269 km away · intensity VIII
Moderate damage ($1–5M)tsunami

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

Nearby trackers