M5.1 earthquake in Near the coast of Libertador O'Higgins, Chile

Sunday, January 23, 2011, 09:58:59 UTC · 34.998°S, 72.378°W

A magnitude 5.1 earthquake struck in Near the coast of Libertador O'Higgins, Chile on Sunday, January 23, 2011, 09:58:59 UTC, at a depth of 35.0 km (shallow). USGS received 9 “Did You Feel It?” reports, with a maximum reported intensity of III (weak). It is the strongest earthquake within 300 km since an M5.3 on January 19, 2011.

Magnitude: 5.1; Moderate · mb
Depth: 35 km; Shallow
Felt reports: 9; Max intensity III
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

674 tons of TNT

That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.

Tectonic setting

108 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

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
Santiago, Metropolitana, Chile	II · Weak	3	236 km
Parral, Maule, Chile	III · Weak	1	140 km
Linares, Maule, Chile	III · Weak	1	122 km
Talca, Maule, Chile	III · Weak	1	87 km
Teno, Maule, Chile	III · Weak	1	117 km
Chillán, Bío Bío, Chile	II · Weak	1	182 km
Tomé, Bío Bío, Chile	II · Weak	1	189 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 5 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M6.7 on February 14, 2011. 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 663 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 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 · 140 km away · intensity X
30,000 deaths$920 million damagetsunami
1906M8.2
South Central
17 Aug 1906 · 225 km away · intensity XI
4,000 deaths$100 million damagetsunami
2010M8.8
Maule, Concepcion, Talcahuano
27 Feb 2010 · 134 km away · intensity IX
558 deaths$30 billion damagetsunami
1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 34 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 216 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
1971M7.8
Central
9 Jul 1971 · 298 km away · intensity IX
83 deaths$236 million damagetsunami

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

Nearby trackers