Reviewed by USGSChile42y ago
M4.3 earthquake 59 km W of Cartagena, Chile
Monday, April 22, 1985, 06:53:40 UTC · 33.515°S, 72.250°W
A magnitude 4.3 earthquake struck 59 km W of Cartagena, Chile on Monday, April 22, 1985, 06:53:40 UTC, at a depth of 33.0 km (shallow).
- Magnitude
- 4.3
- 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
Tectonic setting
58 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 lists 6 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.6 on May 19, 1985. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.638 km W of San Antonio, Chile41y ago · 23 km SE of this epicenter
- 4.953 km W of Cartagena, Chile41y ago · 7 km E of this epicenter
- 4.678 km WSW of San Antonio, Chile41y ago · 38 km S of this epicenter
- 5.671 km WSW of San Antonio, Chile41y ago · 42 km S of this epicenter
- 4.7Off the coast of Valparaiso, Chile41y ago · 23 km SE of this epicenter
- 4.776 km W of Cartagena, Chile42y ago · 17 km W of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 230 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 · 147 km NE of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 264 km N of this epicenter
- 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 55 km NE of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 142 km NE of this epicenter
- 7.730 km NNE of Constitución, ChileDecember 1, 1928 · 174 km S of this epicenter
- 7.7103 km NW of Constitución, ChileJanuary 30, 1914 · 170 km SW of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 148 km NE of this epicenter
- 7.419 km S of Valparaíso, ChileMarch 4, 1985 · 64 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 32 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 5,032 recorded deaths. The most severe:
- 1906M8.2
South Central
17 Aug 1906 · 62 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1965M7.3
Central
28 Mar 1965 · 158 km away
400 deaths$125 million damage
- 1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 167 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
- 1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 66 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
- 1971M7.8
Central
9 Jul 1971 · 149 km away · intensity IX
83 deaths$236 million damagetsunami
- 1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 62 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.