Reviewed by USGSChile84y ago
M8.1 earthquake 45 km NNW of Illapel, Chile
Tuesday, April 6, 1943, 16:07:18 UTC · 31.262°S, 71.368°W
A magnitude 8.1 earthquake struck 45 km NNW of Illapel, Chile on Tuesday, April 6, 1943, 16:07:18 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M8.2 on August 17, 1906.
- Magnitude
- 8.1
- Great · mw
- Depth
- 35 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VII
- Very strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 400 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
21 megatons of TNT
That is about 1,415 times the Hiroshima bomb. It released about 44,668 times the energy of a magnitude 5.0.
Tectonic setting
122 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
35 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 400 km
USGS lists 3 M2.5+ earthquakes within 400 km in the following 30 days; the largest was M6.5 on April 15, 1943. 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 34 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 · 127 km S of this epicenter
- 7.237 km S of San Antonio, ChileMarch 18, 1931 · 297 km S of this epicenter
- 7.086 km NW of La Serena, ChileMarch 19, 1904 · 225 km N of this epicenter
- 6.9103 km NNW of Coquimbo, ChileMay 20, 1918 · 238 km N of this epicenter
- 6.972 km WNW of Calingasta, ArgentinaJuly 27, 1917 · 128 km E of this epicenter
- 6.957 km W of Ovalle, ChileFebruary 15, 1917 · 92 km NW of this epicenter
- 6.8121 km WSW of Coquimbo, ChileNovember 17, 1922 · 142 km NW of this epicenter
- 6.726 km S of Nueve de Julio, ArgentinaDecember 17, 1920 · 289 km E 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 18,493 recorded deaths. The most severe:
- 1861
Mendoza, San Luiz
20 Mar 1861 · 296 km away · intensity IX
14,000 deathsExtreme damage ($25M+)tsunami
- 1906M8.2
South Central
17 Aug 1906 · 202 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1920M6.7
Mendoza
17 Dec 1920 · 289 km away · intensity VIII
400 deathsSevere damage ($5–24M)
- 1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 202 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami
- 1943M8.2
Illapel
6 Apr 1943 · 83 km away
11 deathsLimited damage (under $1M)tsunami
- 1730M9.1
Valparaiso
8 Jul 1730 · 138 km away · intensity XI
5 deathsSevere damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.