Reviewed by USGSArgentina49y ago
M5.1 earthquake 58 km SSW of San Agustín de Valle Fértil, Argentina
Sunday, January 1, 1978, 10:50:58 UTC · 31.115°S, 67.718°W
A magnitude 5.1 earthquake struck 58 km SSW of San Agustín de Valle Fértil, Argentina on Sunday, January 1, 1978, 10:50:58 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M5.3 on December 23, 1977.
- Magnitude
- 5.1
- Moderate · mb
- Depth
- 35 km
- Shallow
- 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
674 tons of TNT
That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.
Tectonic setting
467 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: shallow
35 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
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 75 km
USGS lists 4 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.8 on January 17, 1978. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 112 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.4San Juan, ArgentinaNovember 23, 1977 · 11 km NW of this epicenter
- 6.94 km ESE of Chimbas, ArgentinaJanuary 15, 1944 · 85 km SW of this epicenter
- 6.972 km WNW of Calingasta, ArgentinaJuly 27, 1917 · 224 km W of this epicenter
- 6.88 km W of Nueve de Julio, ArgentinaJune 11, 1952 · 95 km SW of this epicenter
- 6.726 km S of Nueve de Julio, ArgentinaDecember 17, 1920 · 110 km SW of this epicenter
- 6.725 km SE of Monte Patria, ChileNovember 14, 1927 · 290 km W of this epicenter
- 6.527 km SE of Caucete, ArgentinaJuly 3, 1941 · 82 km S of this epicenter
- 6.367 km E of Caucete, ArgentinaNovember 24, 1977 · 57 km S of this epicenter
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 24,484 recorded deaths. The most severe:
- 1861
Mendoza, San Luiz
20 Mar 1861 · 213 km away · intensity IX
14,000 deathsExtreme damage ($25M+)tsunami
- 1944M6.9
San Juan Province
15 Jan 1944 · 85 km away · intensity IX
10,000 deaths$100 million damage
- 1920M6.7
Mendoza
17 Dec 1920 · 110 km away · intensity VIII
400 deathsSevere damage ($5–24M)
- 1977M7.5
San Juan Province: Mendoza
23 Nov 1977 · 12 km away · intensity IX
65 deaths$80 million damage
- 1899
La Rioja
12 Apr 1899 · 282 km away · intensity VIII
11 deathsModerate damage ($1–5M)
- 1952M6.8
San Juan
11 Jun 1952 · 95 km away · intensity VIII
5 deathsModerate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.