Reviewed by USGSPapua New Guinea55y ago
M6.3 earthquake 139 km WNW of Panguna, Papua New Guinea
Monday, August 9, 1971, 12:12:01 UTC · 5.923°S, 154.290°E
A magnitude 6.3 earthquake struck 139 km WNW of Panguna, Papua New Guinea on Monday, August 9, 1971, 12:12:01 UTC, at a depth of 50.3 km (shallow). It is the strongest earthquake within 300 km since an M6.4 on July 28, 1971.
- Magnitude
- 6.3
- Strong · mw
- Depth
- 50 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
51 kilotons of TNT
That is about 3 times the Hiroshima bomb. It released about 106 times the energy of a magnitude 5.0.
Tectonic setting
28 km
from the nearest mapped plate boundary, between the Pacific and North Bismarck plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
50 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 100 km
USGS lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M6.0 on August 13, 1971. 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 286 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 · 133 km N of this epicenter
- 8.11971 Bougainville EarthquakeJuly 26, 1971 · 170 km NW of this epicenter
- 8.01971 New Britain EarthquakeJuly 14, 1971 · 69 km NW of this epicenter
- 8.060 km SE of Kokopo, Papua New GuineaJanuary 1, 1916 · 225 km NW of this epicenter
- 7.885 km S of Panguna, Papua New GuineaJanuary 30, 1939 · 177 km SE of this epicenter
- 7.874 km SSW of Kokopo, Papua New GuineaFebruary 2, 1920 · 273 km NW of this epicenter
- 7.7152 km SE of Kokopo, Papua New GuineaSeptember 29, 1946 · 132 km NW of this epicenter
- 7.467 km E of Kokopo, Papua New GuineaApril 23, 1953 · 227 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 24 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 516 recorded deaths. The most severe:
- 1937
Keravia, Rabaul, Kokopo
28 May 1937 · 295 km away · intensity VIII
507 deathsLimited damage (under $1M)tsunami
- 1939M7.7
Bougainville Island
30 Jan 1939 · 177 km away
5 deathsModerate damage ($1–5M)tsunami
- 1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 64 km away · intensity IX
3 deathsUnder $1 million damagetsunami
- 1878
Bismarck Sea
4 Feb 1878 · 293 km away
1 deathtsunami
- 1959M7.3
Solomon Islands
17 Aug 1959 · 258 km away
Severe damage ($5–24M)tsunami
- 1967M6.4
Bismarck Sea
13 Aug 1967 · 261 km away
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.