Reviewed by USGSPeru96y ago
M6.0 earthquake 164 km SW of Pacasmayo, Peru
Monday, September 21, 1931, 21:36:58 UTC · 8.289°S, 80.772°W
A magnitude 6.0 earthquake struck 164 km SW of Pacasmayo, Peru on Monday, September 21, 1931, 21:36:58 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on April 3, 1931.
- Magnitude
- 6.0
- Strong · mw
- Depth
- 10 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
17 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 36 times the energy of a magnitude 5.0.
Tectonic setting
45 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
10 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 6 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 · 255 km S of this epicenter
- 6.3115 km SSW of Sechura, PeruDecember 27, 1925 · 207 km N of this epicenter
- 6.1252 km SW of Pacasmayo, PeruJuly 14, 1927 · 88 km SW of this epicenter
- 6.1123 km WSW of Puerto Casma, PeruApril 3, 1931 · 232 km SE of this epicenter
- 6.023 km SE of Bernal, PeruMarch 13, 1927 · 298 km N of this epicenter
- 5.958 km WSW of Puerto Santa, PeruNovember 21, 1927 · 204 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 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 · 210 km away · intensity IX
1,500 deathsSevere damage ($5–24M)
- 1912M7.0
Huancabamba,Cajamarca; Ecuador: Guayaquil
24 Jul 1912 · 299 km away · intensity X
Severe damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.