Reviewed by USGSChile99y ago
M7.0 earthquake 64 km NNE of Antofagasta, Chile
Tuesday, November 20, 1928, 20:35:12 UTC · 23.157°S, 70.057°W
A magnitude 7.0 earthquake struck 64 km NNE of Antofagasta, Chile on Tuesday, November 20, 1928, 20:35:12 UTC, at a depth of 45.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.0
- Major · mw
- Depth
- 45 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
529 kilotons of TNT
That is about 35 times the Hiroshima bomb. It released about 1,109 times the energy of a magnitude 5.0.
Tectonic setting
134 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
45 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 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M5.9 on November 29, 1928. 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 7 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.881 km WSW of Calama, ChileDecember 23, 1916 · 61 km NE of this epicenter
- 6.6152 km WNW of Tocopilla, ChileOctober 22, 1920 · 233 km NW of this epicenter
- 6.697 km SW of Antofagasta, ChileAugust 5, 1907 · 163 km SW of this epicenter
- 6.37 km SSE of Taltal, ChileMay 15, 1925 · 260 km S of this epicenter
- 6.221 km NW of Antofagasta, ChileJanuary 1, 1926 · 63 km SW of this epicenter
- 6.251 km WNW of Taltal, ChileAugust 17, 1923 · 240 km S of this epicenter
- 5.569 km E of Taltal, ChileMarch 14, 1927 · 258 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,385 recorded deaths. The most severe:
- 1877M8.3
Off North Coast
10 May 1877 · 190 km away · intensity XI
2,385 deaths$2 million damagetsunami
- 1836M7.5
Cobija
3 Jul 1836 · 67 km away
tsunami
- 1928M7.1
Northern
20 Nov 1928 · 86 km away
tsunami
- 1869M6.8
Iquique
21 Aug 1869 · 240 km away
tsunami
- 1870
Chile
22 Apr 1870 · 139 km away · intensity X
- 1873
Antofagasta
19 Nov 1873 · 60 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.