M7.3 earthquake 27 km NNW of El Hoyo, Argentina

Sunday, June 23, 1991, 21:22:28 UTC · 26.802°S, 63.349°W

A magnitude 7.3 earthquake struck 27 km NNW of El Hoyo, Argentina on Sunday, June 23, 1991, 21:22:28 UTC, at a depth of 558.0 km (deep). It is the strongest earthquake within 300 km since an M7.3 on December 7, 1912.

Magnitude: 7.3; Major · mw
Depth: 558 km; Deep
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

1.3 megatons of TNT

That is about 89 times the Hiroshima bomb. It released about 2,818 times the energy of a magnitude 5.0.

Tectonic setting

601 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: deep

558 km

Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.

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 3 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.6 on June 23, 1991. 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 44 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 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 31 recorded deaths. The most severe:

1930M6.1
La Poma
24 Dec 1930 · 280 km away · intensity VIII
31 deathsSevere damage ($5–24M)
1948M6.9
Salta
25 Aug 1948 · 276 km away · intensity IX
Moderate damage ($1–5M)
1817
Santiago Del Estero Province
4 Jul 1817 · 175 km away · intensity VIII
Moderate damage ($1–5M)
1826
Candelaria, Trancas, Zarate, El Tala
19 Jan 1826 · 128 km away · intensity VII
Moderate damage ($1–5M)
1912M7.5
Santiago Del Estero Province
7 Dec 1912 · 258 km away
1916M7.5
Argentina
21 Jun 1916 · 192 km away

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

Nearby trackers