Reviewed by USGSChile84y ago
M6.4 earthquake 64 km W of Illapel, Chile
Wednesday, April 7, 1943, 23:17:54 UTC · 31.575°S, 71.843°W
A magnitude 6.4 earthquake struck 64 km W of Illapel, Chile on Wednesday, April 7, 1943, 23:17:54 UTC, at a depth of 25.0 km (shallow). It is the strongest earthquake within 300 km since an M8.1 on April 6, 1943.
- Magnitude
- 6.4
- Strong · mw
- Depth
- 25 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
62 kilotons of TNT
That is about 4 times the Hiroshima bomb. It released about 130 times the energy of a magnitude 5.0.
Tectonic setting
80 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
25 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 100 km
USGS lists 1 M2.5+ earthquake within 100 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 31 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 · 101 km SE of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 57 km NE of this epicenter
- 7.237 km S of San Antonio, ChileMarch 18, 1931 · 263 km S of this epicenter
- 7.086 km NW of La Serena, ChileMarch 19, 1904 · 257 km N of this epicenter
- 6.9103 km NNW of Coquimbo, ChileMay 20, 1918 · 267 km N of this epicenter
- 6.972 km WNW of Calingasta, ArgentinaJuly 27, 1917 · 182 km E of this epicenter
- 6.957 km W of Ovalle, ChileFebruary 15, 1917 · 118 km N of this epicenter
- 6.8121 km WSW of Coquimbo, ChileNovember 17, 1922 · 142 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 28 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 4,093 recorded deaths. The most severe:
- 1906M8.2
South Central
17 Aug 1906 · 159 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 159 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami
- 1943M8.2
Illapel
6 Apr 1943 · 93 km away
11 deathsLimited damage (under $1M)tsunami
- 1730M9.1
Valparaiso
8 Jul 1730 · 108 km away · intensity XI
5 deathsSevere damage ($5–24M)tsunami
- 1903M6.0
Mendoza
12 Aug 1903 · 266 km away · intensity VIII
3 deathsModerate damage ($1–5M)
- 1880M7.7
Illapel
15 Aug 1880 · 63 km away · intensity X
2 deathsSevere damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.