M5.2 earthquake off the coast of Michoacan, Mexico

Sunday, October 22, 1978, 14:07:00 UTC · 15.176°N, 104.448°W

A magnitude 5.2 earthquake struck off the coast of Michoacan, Mexico on Sunday, October 22, 1978, 14:07:00 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.2 on January 31, 1975.

Magnitude: 5.2; Moderate · mb
Depth: 33 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

951 tons of TNT

That is about 1/16 of the Hiroshima bomb. It released about 2 times the energy of a magnitude 5.0.

Tectonic setting

23 km

from the nearest mapped plate boundary, between the Cocos and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

33 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 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.2 on October 22, 1978. 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.

5.2off the coast of Michoacan, Mexico48y ago · 16 km N of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 7 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

Nearby trackers