M8.0 earthquake 1985 Michoacan, Mexico Earthquake

Thursday, September 19, 1985, 13:17:47 UTC · 18.190°N, 102.533°W

A magnitude 8.0 earthquake struck 1985 Michoacan, Mexico Earthquake on Thursday, September 19, 1985, 13:17:47 UTC, at a depth of 27.9 km (shallow). It is the strongest earthquake within 300 km since an M8.1 on June 3, 1932.

Magnitude: 8.0; Great · mw
Depth: 28 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: 400 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

15 megatons of TNT

That is about 1,002 times the Hiroshima bomb. It released about 31,623 times the energy of a magnitude 5.0.

Tectonic setting

87 km

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

Depth: shallow

28 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 400 km

USGS lists 48 M2.5+ earthquakes within 400 km in the following 30 days; the largest was M7.6 on September 21, 1985. 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 118 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 43 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 14,318 recorded deaths. The most severe:

1985M8.1
Michoacan: Mexico City
19 Sep 1985 · 0 km away · intensity IX
9,500 deaths$4.0 billion damagetsunami
1806M7.5
Jalisco,Oaxaca,Michoacan
25 Mar 1806 · 155 km away · intensity VIII
2,000 deathsExtreme damage ($25M+)
1818M8.2
Morelos-Guerrero,Mexico City,Guadalajara
31 May 1818 · 179 km away · intensity X
2,000 deathsSevere damage ($5–24M)tsunami
1932M8.1
Near Coast Of Jalisco
3 Jun 1932 · 216 km away · intensity X
400 deathsSevere damage ($5–24M)tsunami
1941M7.6
Michoacan, Colima, Jalisco
15 Apr 1941 · 73 km away · intensity VII
84 deaths$2 million damagetsunami
1964M7.3
Guerrero
6 Jul 1964 · 204 km away
78 deathsSevere damage ($5–24M)

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

Nearby trackers