Reviewed by USGSArgentina3d ago
M5.3 earthquake 51 km WSW of Arauco, Argentina
Wednesday, September 23, 2026, 09:21:14 UTC · 28.730°S, 67.291°W
A magnitude 5.3 earthquake struck 51 km WSW of Arauco, Argentina on Wednesday, September 23, 2026, 09:21:14 UTC, at a depth of 121.5 km (intermediate). USGS received 4 “Did You Feel It?” reports, with a maximum reported intensity of IV (light). It is the strongest earthquake within 300 km since an M5.4 on May 1, 2025.
- Magnitude
- 5.3
- Moderate · mww
- Depth
- 122 km
- Intermediate
- Felt reports
- 4
- Max intensity IV
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
1 kilotons of TNT
That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.
Tectonic setting
468 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
122 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
Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.
| Place | Intensity | Reports | Distance |
|---|---|---|---|
| La Rioja, La Rioja, Argentina | IV · Light | 3 | 149 km |
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 75 km
USGS has not published any M2.5+ earthquake within 75 km since this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 256 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.594 km ENE of Vallenar, ChileNovember 11, 1922 · 255 km W of this epicenter
- 7.4San Juan, ArgentinaNovember 23, 1977 · 260 km S of this epicenter
- 7.032 km NW of Fiambalá, ArgentinaAugust 3, 1920 · 151 km N of this epicenter
- 6.410 km WNW of Tinogasta, ArgentinaNovember 29, 1943 · 85 km NW of this epicenter
- 6.485 km SW of Antofagasta de la Sierra, ArgentinaDecember 4, 1918 · 233 km N of this epicenter
- 6.412 km SSW of San Fernando del Valle de Catamarca, ArgentinaSeptember 7, 2004 · 143 km E of this epicenter
- 6.430 km SSE of Londres, ArgentinaJune 10, 1985 · 91 km N of this epicenter
- 6.1115 km ESE of Vallenar, ChileJuly 19, 1980 · 234 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 777 recorded deaths. The most severe:
- 1922M8.5
Atacama
11 Nov 1922 · 255 km away · intensity XI
700 deathsSevere damage ($5–24M)tsunami
- 1977M7.5
San Juan Province: Mendoza
23 Nov 1977 · 271 km away · intensity IX
65 deaths$80 million damage
- 1899
La Rioja
12 Apr 1899 · 109 km away · intensity VIII
11 deathsModerate damage ($1–5M)
- 2004M6.1
Catamarca
7 Sep 2004 · 143 km away
1 deathLimited damage (under $1M)
- 2002M6.0
Aminga, Anillaco, Agua Blanca, Chuquis
28 May 2002 · 53 km away · intensity VIII
Moderate damage ($1–5M)
- 1817
Santiago Del Estero Province
4 Jul 1817 · 285 km away · intensity VIII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.