Magnitude5.8

Reviewed by USGSPapua New Guinea54y ago

M5.8 earthquake 182 km SSE of Kokopo, Papua New Guinea

Monday, August 21, 1972, 08:47:07 UTC · 5.826°S, 152.986°E

A magnitude 5.8 earthquake struck 182 km SSE of Kokopo, Papua New Guinea on Monday, August 21, 1972, 08:47:07 UTC, at a depth of 37.5 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on August 18, 1972.

Magnitude
5.8
Moderate · mw
Depth
38 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: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

7 kilotons of TNT

That is about 1/2 of the Hiroshima bomb. It released about 14 times the energy of a magnitude 5.0.

Tectonic setting

12 km

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

Depth: shallow

38 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 M5.7 on September 4, 1972. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M61h6h1d3d7d14d30dMainshock M5.8
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.7192 km S of Kokopo, Papua New Guinea54y ago · 54 km SW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 369 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 27 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 520 recorded deaths. The most severe:

  1. 1937

    Keravia, Rabaul, Kokopo

    28 May 1937 · 193 km away · intensity VIII

    507 deathsLimited damage (under $1M)tsunami

  2. 1939M7.7

    Bougainville Island

    30 Jan 1939 · 300 km away

    5 deathsModerate damage ($1–5M)tsunami

  3. 1941M7.4

    Bismarck Sea

    13 Jan 1941 · 210 km away

    4 deathsModerate damage ($1–5M)tsunami

  4. 1971M7.9

    New Ireland: Bougainville

    14 Jul 1971 · 107 km away · intensity IX

    3 deathsUnder $1 million damagetsunami

  5. 1878

    Bismarck Sea

    4 Feb 1878 · 193 km away

    1 deathtsunami

  6. 1967M6.4

    Bismarck Sea

    13 Aug 1967 · 167 km away

    Severe damage ($5–24M)tsunami

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

Nearby trackers

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