Reviewed by USGSChile15y ago
M4.0 earthquake 48 km NE of Constitución, Chile
Tuesday, December 21, 2010, 18:05:09 UTC · 35.076°S, 71.984°W
A magnitude 4.0 earthquake struck 48 km NE of Constitución, Chile on Tuesday, December 21, 2010, 18:05:09 UTC, at a depth of 34.9 km (shallow).
- Magnitude
- 4.0
- Light · mb
- Depth
- 35 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
15 tons of TNT
That is about 1/998 of the Hiroshima bomb. A magnitude 5.0 releases about 32 times more energy.
Tectonic setting
144 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
35 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.2 on January 2, 2011. 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 645 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.82010 Maule, Chile EarthquakeFebruary 27, 2010 · 143 km SW of this epicenter
- 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 216 km N of this epicenter
- 7.826 km WNW of San Carlos, ChileJanuary 25, 1939 · 137 km S of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 284 km N of this epicenter
- 7.730 km NNE of Constitución, ChileDecember 1, 1928 · 26 km W of this epicenter
- 7.7103 km NW of Constitución, ChileJanuary 30, 1914 · 126 km W of this epicenter
- 7.523 km SE of Chiguayante, ChileMay 6, 1953 · 238 km S of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 294 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 40 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35,321 recorded deaths. The most severe:
- 1939M8.3
Chillan
25 Jan 1939 · 133 km away · intensity X
30,000 deaths$920 million damagetsunami
- 1906M8.2
South Central
17 Aug 1906 · 231 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 2010M8.8
Maule, Concepcion, Talcahuano
27 Feb 2010 · 143 km away · intensity IX
558 deaths$30 billion damagetsunami
- 1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 9 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
- 1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 218 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
- 1971M7.8
Central
9 Jul 1971 · 295 km away · intensity IX
83 deaths$236 million damagetsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.