M7.6 earthquake 12 km SSE of Vallecitos de Zaragoza, Mexico

Wednesday, March 14, 1979, 11:07:16 UTC · 17.813°N, 101.276°W

A magnitude 7.6 earthquake struck 12 km SSE of Vallecitos de Zaragoza, Mexico on Wednesday, March 14, 1979, 11:07:16 UTC, at a depth of 49.0 km (shallow). It is the strongest earthquake within 300 km since an M7.6 on July 28, 1957.

Magnitude: 7.6; Major · ms
Depth: 49 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VIII; Severe (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

3.8 megatons of TNT

That is about 252 times the Hiroshima bomb. It released about 7,943 times the energy of a magnitude 5.0.

Tectonic setting

98 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

49 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 12 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.5 on March 14, 1979. 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 113 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 54 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,534 recorded deaths. The most severe:

1806M7.5
Jalisco,Oaxaca,Michoacan
25 Mar 1806 · 293 km away · intensity VIII
2,000 deathsExtreme damage ($25M+)
1912M6.7
Central, Acambay, Tixmadeje
19 Nov 1912 · 243 km away
202 deathsSevere damage ($5–24M)
1941M7.6
Michoacan, Colima, Jalisco
15 Apr 1941 · 205 km away · intensity VII
84 deaths$2 million damagetsunami
1964M7.3
Guerrero
6 Jul 1964 · 80 km away
78 deathsSevere damage ($5–24M)
1957M7.9
Acapulco,Mexico City
28 Jul 1957 · 273 km away · intensity VII
65 deaths$25 million damagetsunami
1973M7.5
S, Farias, Tecoman
30 Jan 1973 · 197 km away
56 deathsModerate damage ($1–5M)tsunami

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

Nearby trackers