M5.6 earthquake 34 km WNW of San Antonio de los Cobres, Argentina

Wednesday, April 18, 2007, 01:08:08 UTC · 24.082°S, 66.626°W

A magnitude 5.6 earthquake struck 34 km WNW of San Antonio de los Cobres, Argentina on Wednesday, April 18, 2007, 01:08:08 UTC, at a depth of 172.2 km (intermediate). It is the strongest earthquake within 300 km since an M5.7 on November 14, 2006.

Magnitude: 5.6; Moderate · mwc
Depth: 172 km; Intermediate
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: 75 km aftershock search area

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

285 km

from the nearest mapped plate boundary, between the Altiplano and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: intermediate

172 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

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 75 km

USGS lists 5 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.4 on May 4, 2007. 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 375 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 12 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 32 recorded deaths. The most severe:

1930M6.1
La Poma
24 Dec 1930 · 167 km away · intensity VIII
31 deathsSevere damage ($5–24M)
1950M8.0
Chile-Argentina
9 Dec 1950 · 110 km away · intensity VII
1 death
1844M6.5
Salta, Jujuy, Tucuman
19 Oct 1844 · 120 km away · intensity VII
Severe damage ($5–24M)
1948M6.9
Salta
25 Aug 1948 · 220 km away · intensity IX
Moderate damage ($1–5M)
1959M6.6
Salta
12 May 1959 · 208 km away · intensity VIII
Moderate damage ($1–5M)
1863
Jujuy
14 Jan 1863 · 174 km away · intensity VIII
Moderate damage ($1–5M)

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

Nearby trackers