Reviewed by USGSPapua New Guinea41y ago
M5.0 earthquake 78 km SSW of Kokopo, Papua New Guinea
Sunday, July 28, 1985, 14:42:09 UTC · 4.985°S, 151.968°E
A magnitude 5.0 earthquake struck 78 km SSW of Kokopo, Papua New Guinea on Sunday, July 28, 1985, 14:42:09 UTC, at a depth of 110.2 km (intermediate). It is the strongest earthquake within 300 km since an M5.0 on July 27, 1985.
- Magnitude
- 5.0
- Moderate · mw
- Depth
- 110 km
- Intermediate
- 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
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
91 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: intermediate
110 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.4 on August 4, 1985. 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 848 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 · 210 km E of this epicenter
- 8.11971 Bougainville EarthquakeJuly 26, 1971 · 135 km E of this epicenter
- 8.01971 New Britain EarthquakeJuly 14, 1971 · 217 km E of this epicenter
- 8.060 km SE of Kokopo, Papua New GuineaJanuary 1, 1916 · 77 km E of this epicenter
- 7.874 km SSW of Kokopo, Papua New GuineaFebruary 2, 1920 · 6 km E of this epicenter
- 7.7152 km SE of Kokopo, Papua New GuineaSeptember 29, 1946 · 154 km E of this epicenter
- 7.6157 km ESE of Kokopo, Papua New GuineaMarch 18, 1983 · 179 km E of this epicenter
- 7.5199 km SSE of Kokopo, Papua New GuineaAugust 17, 1972 · 156 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 33 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 526 recorded deaths. The most severe:
- 1937
Keravia, Rabaul, Kokopo
28 May 1937 · 84 km away · intensity VIII
507 deathsLimited damage (under $1M)tsunami
- 1983M6.4
Ulawun, Rabaul
22 Dec 1983 · 47 km away · intensity V
10 deaths$25 million damage
- 1941M7.4
Bismarck Sea
13 Jan 1941 · 91 km away
4 deathsModerate damage ($1–5M)tsunami
- 1971M7.9
New Ireland: Bougainville
14 Jul 1971 · 221 km away · intensity IX
3 deathsUnder $1 million damagetsunami
- 1985M7.1
New Britain: Bialla, Piona
10 May 1985 · 123 km away · intensity VIII
1 death$1 million damage
- 1878
Bismarck Sea
4 Feb 1878 · 88 km away
1 deathtsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.