Reviewed by USGSChile109y ago
M6.9 earthquake 103 km NNW of Coquimbo, Chile
Monday, May 20, 1918, 17:55:07 UTC · 29.178°S, 71.930°W
A magnitude 6.9 earthquake struck 103 km NNW of Coquimbo, Chile on Monday, May 20, 1918, 17:55:07 UTC, at a depth of 20.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on March 19, 1904.
- Magnitude
- 6.9
- Strong · mw
- Depth
- 20 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VI
- Strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
362 kilotons of TNT
That is about 24 times the Hiroshima bomb. It released about 759 times the energy of a magnitude 5.0.
Tectonic setting
53 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
20 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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 5 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.086 km NW of La Serena, ChileMarch 19, 1904 · 20 km SE of this epicenter
- 6.957 km W of Ovalle, ChileFebruary 15, 1917 · 150 km S of this epicenter
- 6.972 km WNW of Calingasta, ArgentinaJuly 27, 1917 · 269 km SE of this epicenter
- 6.936 km W of Copiapó, ChileSeptember 6, 1910 · 230 km NE of this epicenter
- 6.3137 km WNW of Coquimbo, ChileNovember 28, 1906 · 85 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 18 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 12 recorded deaths. The most severe:
- 1859M7.6
Chile
5 Oct 1859 · 255 km away · intensity X
10 deathsUnder $1 million damagetsunami
- 1880M7.7
Illapel
15 Aug 1880 · 281 km away · intensity X
2 deathsSevere damage ($5–24M)tsunami
- 1819M8.5
Copiapo
12 Apr 1819 · 246 km away · intensity X
Severe damage ($5–24M)tsunami
- 1819M8.0
Copiapo
4 Apr 1819 · 254 km away
Severe damage ($5–24M)
- 1819M8.0
Copiapo
3 Apr 1819 · 254 km away
Moderate damage ($1–5M)
- 1796M7.7
Copiapo, Vallenar, Huasco, Coquimbo
30 Mar 1796 · 255 km away · intensity XI
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.