M6.9 earthquake 39 km SW of Santiago, Peru

Friday, October 28, 2011, 18:54:34 UTC · 14.438°S, 75.966°W

A magnitude 6.9 earthquake struck 39 km SW of Santiago, Peru on Friday, October 28, 2011, 18:54:34 UTC, at a depth of 24.0 km (shallow). USGS received 185 “Did You Feel It?” reports, with a maximum reported intensity of VI (strong). It is the strongest earthquake within 300 km since an M8.0 on August 15, 2007.

Magnitude: 6.9; Strong · mww
Depth: 24 km; Shallow
Felt reports: 185; Max intensity VI
Est. shaking: VII; Very strong (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

338 kilotons of TNT

That is about 22 times the Hiroshima bomb. It released about 708 times the energy of a magnitude 5.0.

Tectonic setting

93 km

from the nearest mapped plate boundary, between the Altiplano and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

24 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

185 people reported feeling this earthquake to USGS; a per-place breakdown is not available 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 100 km

USGS lists 24 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.6 on October 28, 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 309 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 43 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 736 recorded deaths. The most severe:

2007M8.0
Ica, Pisco, Lima
15 Aug 2007 · 136 km away · intensity VIII
596 deaths$600 million damagetsunami
1813
Ica
30 Mar 1813 · 72 km away · intensity VII
32 deathsModerate damage ($1–5M)
1942M8.2
Ica, Nazca
24 Aug 1942 · 63 km away · intensity IX
30 deathsSevere damage ($5–24M)tsunami
1996M7.7
Chincha Alta, Acari, Nazca, Marcona
12 Nov 1996 · 69 km away · intensity VIII
14 deathsExtreme damage ($25M+)tsunami
1974M6.3
Lima, Yauyos
5 Jan 1974 · 241 km away
10 deathsSevere damage ($5–24M)
1981M5.2
Central
22 Jun 1981 · 211 km away
10 deaths$5 million damage

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

Nearby trackers