M4.9 earthquake 78 km W of San Antonio de los Cobres, Argentina

Saturday, October 27, 2007, 21:54:21 UTC · 24.260°S, 67.088°W

A magnitude 4.9 earthquake struck 78 km W of San Antonio de los Cobres, Argentina on Saturday, October 27, 2007, 21:54:21 UTC, at a depth of 164.3 km (intermediate). It is the strongest earthquake within 300 km since an M5.3 on August 4, 2007.

Magnitude: 4.9; Light · mb
Depth: 164 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

338 tons of TNT

That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.

Tectonic setting

305 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

164 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 M4.2 on November 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 394 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 37 recorded deaths. The most severe:

1930M6.1
La Poma
24 Dec 1930 · 193 km away · intensity VIII
31 deathsSevere damage ($5–24M)
1953M7.4
Northern
7 Dec 1953 · 291 km away
3 deaths$7 million damage
1936M7.3
Taltal
13 Jul 1936 · 296 km away
1 deathModerate damage ($1–5M)tsunami
1971M6.3
Catalina, Antofagasta
17 Jun 1971 · 254 km away · intensity V
1 deathModerate damage ($1–5M)
1950M8.0
Chile-Argentina
9 Dec 1950 · 94 km away · intensity VII
1 death
1844M6.5
Salta, Jujuy, Tucuman
19 Oct 1844 · 137 km away · intensity VII
Severe damage ($5–24M)

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

Nearby trackers