M5.6 earthquake 44 km W of Constitución, Chile

Sunday, March 28, 2010, 21:43:13 UTC · 35.406°S, 72.897°W

A magnitude 5.6 earthquake struck 44 km W of Constitución, Chile on Sunday, March 28, 2010, 21:43:13 UTC, at a depth of 21.5 km (shallow). USGS received 16 “Did You Feel It?” reports, with a maximum reported intensity of IV (light). It is the strongest earthquake within 300 km since an M6.0 on March 28, 2010.

Magnitude: 5.6; Moderate · mwc
Depth: 22 km; Shallow
Felt reports: 16; Max intensity IV
Est. shaking: V; Moderate (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

4 kilotons of TNT

That is about 1/4 of the Hiroshima bomb. It released about 8 times the energy of a magnitude 5.0.

Tectonic setting

83 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

22 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

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Concepción, Bío Bío, Chile	III · Weak	4	160 km
Santiago, Metropolitana, Chile	III · Weak	4	300 km
Rengo, Libertador General Bernardo OʿHiggins, Chile	IV · Light	2	216 km
Talca, Maule, Chile	III · Weak	2	114 km
Viña del Mar, Valparaíso, Chile	II · Weak	1	294 km
Talcahuano, Bío Bío, Chile	II · Weak	1	151 km
Colina, Metropolitana, Chile	II · Weak	1	272 km

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 75 km

USGS lists 24 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.1 on April 6, 2010. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 561 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 36 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35,282 recorded deaths. The most severe:

1939M8.3
Chillan
25 Jan 1939 · 110 km away · intensity X
30,000 deaths$920 million damagetsunami
1906M8.2
South Central
17 Aug 1906 · 280 km away · intensity XI
4,000 deaths$100 million damagetsunami
2010M8.8
Maule, Concepcion, Talcahuano
27 Feb 2010 · 80 km away · intensity IX
558 deaths$30 billion damagetsunami
1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 93 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 275 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
1822M8.5
Valparaiso, Quillota, Concon, Aconcagua
20 Nov 1822 · 280 km away · intensity XI
72 deathsExtreme damage ($25M+)tsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers