M7.7 earthquake 44 km SSE of Cañete, Chile

Saturday, May 10, 1975, 14:27:38 UTC · 38.183°S, 73.232°W

A magnitude 7.7 earthquake struck 44 km SSE of Cañete, Chile on Saturday, May 10, 1975, 14:27:38 UTC, at a depth of 6.0 km (shallow). It is the strongest earthquake within 300 km since an M9.5 on May 22, 1960.

Magnitude: 7.7; Major · ms
Depth: 6 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VII; Very strong (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

5.4 megatons of TNT

That is about 355 times the Hiroshima bomb. It released about 11,220 times the energy of a magnitude 5.0.

Tectonic setting

124 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

6 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 200 km

USGS lists 20 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.8 on May 28, 1975. 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 80 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 20 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 32,416 recorded deaths. The most severe:

1939M8.3
Chillan
25 Jan 1939 · 232 km away · intensity X
30,000 deaths$920 million damagetsunami
1960M9.5
Puerto Montt, Valdivia
22 May 1960 · 16 km away · intensity XII
2,226 deaths$1.0 billion damagetsunami
1751M8.5
Concepcion, Chillan, Talca, Tutuben, Curico
25 May 1751 · 206 km away · intensity XI
65 deathsSevere damage ($5–24M)tsunami
1949M7.3
Angol, Traiguen
20 Apr 1949 · 31 km away
57 deathsModerate damage ($1–5M)tsunami
1835M8.2
Concepcion
20 Feb 1835 · 151 km away · intensity XI
53 deathsExtreme damage ($25M+)tsunami
1953M7.6
Chillan, Concepcion
6 May 1953 · 198 km away · intensity X
9 deaths$500 million damagetsunami

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

Nearby trackers