Reviewed by USGSPapua New Guinea51y ago
M5.4 earthquake in Bougainville region, Papua New Guinea
Sunday, November 23, 1975, 00:36:35 UTC · 6.342°S, 154.836°E
A magnitude 5.4 earthquake struck in Bougainville region, Papua New Guinea on Sunday, November 23, 1975, 00:36:35 UTC, at a depth of 56.0 km (shallow). It is the strongest earthquake within 300 km since an M5.6 on November 19, 1975.
- Magnitude
- 5.4
- Moderate · mb
- Depth
- 56 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
2 kilotons of TNT
That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.
Tectonic setting
34 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
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 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.5 on December 14, 1975. 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 491 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 · 202 km NW of this epicenter
- 8.11971 Bougainville EarthquakeJuly 26, 1971 · 246 km NW of this epicenter
- 8.01971 New Britain EarthquakeJuly 14, 1971 · 145 km NW of this epicenter
- 7.956 km WSW of Panguna, Papua New GuineaJuly 20, 1975 · 37 km SE of this epicenter
- 7.885 km S of Panguna, Papua New GuineaJanuary 30, 1939 · 103 km SE of this epicenter
- 7.794 km SSW of Panguna, Papua New GuineaJuly 20, 1975 · 92 km S of this epicenter
- 7.7152 km SE of Kokopo, Papua New GuineaSeptember 29, 1946 · 208 km NW of this epicenter
- 7.5199 km SSE of Kokopo, Papua New GuineaAugust 17, 1972 · 216 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 8 recorded deaths. The most severe:
- 1939M7.7
Bougainville Island
30 Jan 1939 · 102 km away
5 deathsModerate damage ($1–5M)tsunami
- 1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 140 km away · intensity IX
3 deathsUnder $1 million damagetsunami
- 1975M7.9
Bismarck Sea: Bougainville
20 Jul 1975 · 37 km away · intensity VIII
Severe damage ($5–24M)tsunami
- 1959M7.3
Solomon Islands
17 Aug 1959 · 182 km away
Severe damage ($5–24M)tsunami
- 1971M8.1
Bismarck Sea Rabaul
26 Jul 1971 · 246 km away · intensity VI
$1 million damagetsunami
- 1974M7.1
Solomon Islands
1 Feb 1974 · 145 km away · intensity VI
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.