Reviewed by USGSChile60y ago
M7.7 earthquake 9 km SSW of Taltal, Chile
Wednesday, December 28, 1966, 08:18:06 UTC · 25.487°S, 70.531°W
A magnitude 7.7 earthquake struck 9 km SSW of Taltal, Chile on Wednesday, December 28, 1966, 08:18:06 UTC, at a depth of 20.0 km (shallow). It is the strongest earthquake within 300 km since an M8.0 on December 4, 1918.
- Magnitude
- 7.7
- Major · mw
- Depth
- 20 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: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
4.8 megatons of TNT
That is about 320 times the Hiroshima bomb. It released about 10,116 times the energy of a magnitude 5.0.
Tectonic setting
104 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
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 200 km
USGS lists 3 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.4 on December 29, 1966. 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 49 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.060 km W of Diego de Almagro, ChileDecember 4, 1918 · 109 km S of this epicenter
- 7.583 km NNE of Taltal, ChileJuly 13, 1936 · 94 km NE of this epicenter
- 7.550 km WNW of Diego de Almagro, ChileJune 8, 1909 · 74 km S of this epicenter
- 7.4Atacama, ChileApril 18, 1939 · 196 km S of this epicenter
- 7.377 km NNE of Taltal, ChileDecember 2, 1960 · 87 km N of this epicenter
- 7.187 km SSE of Antofagasta, ChileJuly 8, 1942 · 133 km N of this epicenter
- 7.064 km NNE of Antofagasta, ChileNovember 20, 1928 · 263 km N of this epicenter
- 7.031 km SSW of Taltal, ChileFebruary 23, 1965 · 22 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 22 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 16 recorded deaths. The most severe:
- 1859M7.6
Chile
5 Oct 1859 · 208 km away · intensity X
10 deathsUnder $1 million damagetsunami
- 1966M7.8
Taltal, Catalina
28 Dec 1966 · 17 km away · intensity VIII
3 deathsUnder $1 million damagetsunami
- 1946M7.9
Northern
2 Aug 1946 · 113 km away
2 deathsSevere damage ($5–24M)tsunami
- 1936M7.3
Taltal
13 Jul 1936 · 122 km away
1 deathModerate damage ($1–5M)tsunami
- 1819M8.5
Copiapo
12 Apr 1819 · 194 km away · intensity X
Severe damage ($5–24M)tsunami
- 1819M8.0
Copiapo
4 Apr 1819 · 214 km away
Severe damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.