Reviewed by USGSPeru96y ago
M6.1 earthquake 123 km WSW of Puerto Casma, Peru
Friday, April 3, 1931, 01:56:16 UTC · 9.895°S, 79.423°W
A magnitude 6.1 earthquake struck 123 km WSW of Puerto Casma, Peru on Friday, April 3, 1931, 01:56:16 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on July 14, 1927.
- Magnitude
- 6.1
- Strong · mw
- 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 earthquake
In context
How big was it, and why here?
Energy released
21 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 45 times the energy of a magnitude 5.0.
Tectonic setting
91 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 4 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.3274 km WSW of Puerto Casma, PeruNovember 17, 1925 · 151 km SW of this epicenter
- 6.3102 km SW of Huarmey, PeruSeptember 29, 1916 · 98 km SE of this epicenter
- 6.1252 km SW of Pacasmayo, PeruJuly 14, 1927 · 258 km NW of this epicenter
- 5.958 km WSW of Puerto Santa, PeruNovember 21, 1927 · 86 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 1,500 recorded deaths. The most severe:
- 1725M7.7
Trujillo, Ancash, Lima
7 Jan 1725 · 110 km away · intensity IX
1,500 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.