Reviewed by USGSChile40y ago
M4.6 earthquake 92 km SSW of Antofagasta, Chile
Saturday, March 7, 1987, 21:45:44 UTC · 24.462°S, 70.631°W
A magnitude 4.6 earthquake struck 92 km SSW of Antofagasta, Chile on Saturday, March 7, 1987, 21:45:44 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.2 on March 7, 1987.
- Magnitude
- 4.6
- Light · mb
- Depth
- 33 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
86 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
33 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 50 km
USGS lists 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.5 on March 15, 1987. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 5.571 km SSW of Antofagasta, Chile40y ago · 21 km N of this epicenter
- 4.859 km SSW of Antofagasta, Chile40y ago · 34 km N of this epicenter
- 4.871 km S of Antofagasta, Chile40y ago · 28 km NE of this epicenter
- 4.979 km SSW of Antofagasta, Chile40y ago · 14 km N of this epicenter
- 4.568 km SW of Antofagasta, Chile40y ago · 36 km NW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 239 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.2121 km SSE of San Pedro de Atacama, ChileDecember 9, 1950 · 281 km E of this epicenter
- 8.060 km W of Diego de Almagro, ChileDecember 4, 1918 · 222 km S of this epicenter
- 7.79 km SSW of Taltal, ChileDecember 28, 1966 · 114 km S of this epicenter
- 7.684 km SSE of Antofagasta, ChileMarch 5, 1987 · 48 km E of this epicenter
- 7.583 km NNE of Taltal, ChileJuly 13, 1936 · 56 km SE of this epicenter
- 7.550 km WNW of Diego de Almagro, ChileJune 8, 1909 · 189 km S of this epicenter
- 7.454 km WSW of Diego de Almagro, ChileOctober 4, 1983 · 231 km S of this epicenter
- 7.334 km NE of Tocopilla, ChileDecember 21, 1967 · 295 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 26 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 13 recorded deaths. The most severe:
- 1983M7.3
Northern: Copoapo-Chanaral
4 Oct 1983 · 231 km away · intensity VII
5 deaths$1 million damagetsunami
- 1966M7.8
Taltal, Catalina
28 Dec 1966 · 116 km away · intensity VIII
3 deathsUnder $1 million damagetsunami
- 1946M7.9
Northern
2 Aug 1946 · 227 km away
2 deathsSevere damage ($5–24M)tsunami
- 1936M7.3
Taltal
13 Jul 1936 · 64 km away
1 deathModerate damage ($1–5M)tsunami
- 1987M7.3
Antofagasta, Arica
5 Mar 1987 · 48 km away · intensity VI
1 deathModerate damage ($1–5M)tsunami
- 1971M6.3
Catalina, Antofagasta
17 Jun 1971 · 185 km away · intensity V
1 deathModerate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.