M4.7 earthquake 87 km WSW of San Antonio de los Cobres, Argentina

Friday, May 18, 2007, 19:31:47 UTC · 24.448°S, 67.145°W

A magnitude 4.7 earthquake struck 87 km WSW of San Antonio de los Cobres, Argentina on Friday, May 18, 2007, 19:31:47 UTC, at a depth of 164.8 km (intermediate). It is the strongest earthquake within 300 km since an M4.9 on May 12, 2007.

Magnitude: 4.7; Light · mb
Depth: 165 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

169 tons of TNT

That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.

Tectonic setting

326 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

165 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 6 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.9 on May 25, 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 377 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 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 34 recorded deaths. The most severe:

1930M6.1
La Poma
24 Dec 1930 · 189 km away · intensity VIII
31 deathsSevere damage ($5–24M)
1936M7.3
Taltal
13 Jul 1936 · 289 km away
1 deathModerate damage ($1–5M)tsunami
1971M6.3
Catalina, Antofagasta
17 Jun 1971 · 238 km away · intensity V
1 deathModerate damage ($1–5M)
1950M8.0
Chile-Argentina
9 Dec 1950 · 111 km away · intensity VII
1 death
1844M6.5
Salta, Jujuy, Tucuman
19 Oct 1844 · 131 km away · intensity VII
Severe damage ($5–24M)
1948M6.9
Salta
25 Aug 1948 · 266 km away · intensity IX
Moderate damage ($1–5M)

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

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