M4.6 earthquake 40 km NW of San Antonio de los Cobres, Argentina

Thursday, March 29, 2007, 09:02:14 UTC · 24.012°S, 66.652°W

A magnitude 4.6 earthquake struck 40 km NW of San Antonio de los Cobres, Argentina on Thursday, March 29, 2007, 09:02:14 UTC, at a depth of 183.0 km (intermediate). It is the strongest earthquake within 300 km since an M4.6 on March 21, 2007.

Magnitude: 4.6; Light · m
Depth: 183 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: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

120 tons of TNT

That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.

Tectonic setting

278 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

183 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 50 km

USGS lists 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.6 on April 18, 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 379 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 13 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35 recorded deaths. The most severe:

1930M6.1
La Poma
24 Dec 1930 · 174 km away · intensity VIII
31 deathsSevere damage ($5–24M)
1953M7.4
Northern
7 Dec 1953 · 298 km away
3 deaths$7 million damage
1950M8.0
Chile-Argentina
9 Dec 1950 · 103 km away · intensity VII
1 death
1844M6.5
Salta, Jujuy, Tucuman
19 Oct 1844 · 128 km away · intensity VII
Severe damage ($5–24M)
1948M6.9
Salta
25 Aug 1948 · 224 km away · intensity IX
Moderate damage ($1–5M)
1959M6.6
Salta
12 May 1959 · 206 km away · intensity VIII
Moderate damage ($1–5M)

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

Nearby trackers