Reviewed by USGSMexico61y ago
M7.4 earthquake 4 km NW of Santa María Zapotitlán, Mexico
Monday, August 23, 1965, 19:46:02 UTC · 16.157°N, 95.876°W
A magnitude 7.4 earthquake struck 4 km NW of Santa María Zapotitlán, Mexico on Monday, August 23, 1965, 19:46:02 UTC, at a depth of 14.5 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on December 23, 1937.
- Magnitude
- 7.4
- Major · mw
- Depth
- 15 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
1.9 megatons of TNT
That is about 126 times the Hiroshima bomb. It released about 3,981 times the energy of a magnitude 5.0.
Tectonic setting
94 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
15 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 3 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.8 on August 24, 1965. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 76 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.015 km ESE of San Gabriel Mixtepec, MexicoJune 17, 1928 · 115 km W of this epicenter
- 7.82 km NW of Teojomulco, MexicoApril 15, 1907 · 154 km W of this epicenter
- 7.65 km SSW of San Miguel Suchixtepec, MexicoJanuary 15, 1931 · 66 km W of this epicenter
- 7.56 km WSW of San Miguel Panixtlahuaca, MexicoOctober 9, 1928 · 167 km W of this epicenter
- 7.48 km ENE of Santiago Xanica, MexicoMarch 22, 1928 · 33 km SW of this epicenter
- 7.43 km W of Huixtepec, MexicoDecember 23, 1937 · 268 km W of this epicenter
- 7.440 km S of Corralero, MexicoAugust 4, 1928 · 253 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 41 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 120 recorded deaths. The most severe:
- 1937M7.2
Central, Puebla: Esperanza, Veracruz
26 Jul 1937 · 263 km away
34 deathsModerate damage ($1–5M)
- 1959M6.9
Gulf Of Campeche
26 Aug 1959 · 285 km away
25 deathsSevere damage ($5–24M)
- 1870M7.9
Oaxaca,Zanaguia,San Francisco Ozolotepec
11 May 1870 · 96 km away
24 deathsSevere damage ($5–24M)tsunami
- 1787M8.6
San Marcos, Oaxaca
28 Mar 1787 · 283 km away · intensity IX
11 deathsSevere damage ($5–24M)tsunami
- 1801M7.0
Oaxaca
5 Oct 1801 · 24 km away
7 deathsSevere damage ($5–24M)
- 1965M7.8
Mexico City, Oaxaca
23 Aug 1965 · 18 km away
6 deathsLimited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.