Reviewed by USGSChile45y ago
M4.5 earthquake 125 km WNW of Cartagena, Chile
Saturday, October 31, 1981, 00:18:23 UTC · 33.335°S, 72.927°W
A magnitude 4.5 earthquake struck 125 km WNW of Cartagena, Chile on Saturday, October 31, 1981, 00:18:23 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.1 on October 22, 1981.
- Magnitude
- 4.5
- Light · mb
- Depth
- 33 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 earthquake
In context
How big was it, and why here?
Energy released
85 tons of TNT
That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.
Tectonic setting
6 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
33 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 50 km
USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 131 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.2The 1906 Valparaiso, Chile EarthquakeAugust 17, 1906 · 176 km NE of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 273 km NE of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 182 km NE of this epicenter
- 7.730 km NNE of Constitución, ChileDecember 1, 1928 · 204 km S of this epicenter
- 7.7103 km NW of Constitución, ChileJanuary 30, 1914 · 163 km S of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 185 km NE of this epicenter
- 7.247 km NW of Cauquenes, ChileDecember 2, 1928 · 265 km S of this epicenter
- 7.237 km S of San Antonio, ChileMarch 18, 1931 · 143 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 29 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 4,860 recorded deaths. The most severe:
- 1906M8.2
South Central
17 Aug 1906 · 94 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1965M7.3
Central
28 Mar 1965 · 192 km away
400 deaths$125 million damage
- 1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 204 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
- 1971M7.8
Central
9 Jul 1971 · 186 km away · intensity IX
83 deaths$236 million damagetsunami
- 1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 94 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami
- 1943M8.2
Illapel
6 Apr 1943 · 300 km away
11 deathsLimited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.