M7.4 earthquake 124 km W of Lebu, Chile

Saturday, February 27, 2010, 08:01:23 UTC · 37.773°S, 75.048°W

A magnitude 7.4 earthquake struck 124 km W of Lebu, Chile on Saturday, February 27, 2010, 08:01:23 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M8.8 on February 27, 2010.

Magnitude: 7.4; Major · mwc
Depth: 35 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: V; Moderate (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

1.9 megatons of TNT

That is about 126 times the Hiroshima bomb. It released about 3,981 times the energy of a magnitude 5.0.

Tectonic setting

38 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

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 200 km

USGS lists 322 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.6 on March 5, 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 168 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 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,909 recorded deaths. The most severe:

1960M9.5
Puerto Montt, Valdivia
22 May 1960 · 150 km away · intensity XII
2,226 deaths$1.0 billion damagetsunami
2010M8.8
Maule, Concepcion, Talcahuano
27 Feb 2010 · 265 km away · intensity IX
558 deaths$30 billion damagetsunami
1949M7.3
Angol, Traiguen
20 Apr 1949 · 138 km away
57 deathsModerate damage ($1–5M)tsunami
1835M8.2
Concepcion
20 Feb 1835 · 207 km away · intensity XI
53 deathsExtreme damage ($25M+)tsunami
1953M7.6
Chillan, Concepcion
6 May 1953 · 267 km away · intensity X
9 deaths$500 million damagetsunami
1898M6.5
Concepcion
23 Jul 1898 · 207 km away · intensity VIII
6 deathsModerate damage ($1–5M)tsunami

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

Nearby trackers