M7.0 earthquake 52 km W of Abra Pampa, Argentina

Wednesday, April 1, 1987, 01:48:08 UTC · 22.767°S, 66.205°W

A magnitude 7.0 earthquake struck 52 km W of Abra Pampa, Argentina on Wednesday, April 1, 1987, 01:48:08 UTC, at a depth of 248.7 km (intermediate). It is the strongest earthquake within 300 km since an M7.7 on November 29, 1957.

Magnitude: 7.0; Major · mw
Depth: 249 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: 200 km aftershock search area

In context

How big was it, and why here?

Energy released

477 kilotons of TNT

That is about 32 times the Hiroshima bomb. It released about 1,000 times the energy of a magnitude 5.0.

Tectonic setting

140 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

249 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 200 km

USGS lists 6 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.5 on April 7, 1987. 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 213 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 17 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 · 272 km away · intensity VIII
31 deathsSevere damage ($5–24M)
1953M7.4
Northern
7 Dec 1953 · 267 km away
3 deaths$7 million damage
1950M8.0
Chile-Argentina
9 Dec 1950 · 155 km away · intensity VII
1 death
1844M6.5
Salta, Jujuy, Tucuman
19 Oct 1844 · 249 km away · intensity VII
Severe damage ($5–24M)
1899M6.9
Southern; Argentina: Salta
23 Mar 1899 · 275 km away · intensity X
Moderate damage ($1–5M)
1948M6.9
Salta
25 Aug 1948 · 263 km away · intensity IX
Moderate damage ($1–5M)

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

Nearby trackers