Reviewed by USGSMexico106y ago
M6.6 earthquake 33 km SSW of Cuyutlán, Mexico
Sunday, May 1, 1921, 05:39:10 UTC · 18.637°N, 104.178°W
A magnitude 6.6 earthquake struck 33 km SSW of Cuyutlán, Mexico on Sunday, May 1, 1921, 05:39:10 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.6 on June 7, 1911.
- Magnitude
- 6.6
- Strong · mw
- Depth
- 15 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
104 kilotons of TNT
That is about 7 times the Hiroshima bomb. It released about 219 times the energy of a magnitude 5.0.
Tectonic setting
53 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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 5 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.619 km W of Arteaga, MexicoJune 7, 1911 · 183 km E of this epicenter
- 6.512 km NW of Tumbiscatío de Ruiz, MexicoJune 7, 1918 · 180 km E of this epicenter
- 6.1202 km SW of La Cruz de Loreto, MexicoJuly 9, 1919 · 294 km W of this epicenter
- 5.96 km SSW of Condémbaro, MexicoMay 16, 1918 · 206 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 22 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 4,083 recorded deaths. The most severe:
- 1806M7.5
Jalisco,Oaxaca,Michoacan
25 Mar 1806 · 49 km away · intensity VIII
2,000 deathsExtreme damage ($25M+)
- 1818M8.2
Morelos-Guerrero,Mexico City,Guadalajara
31 May 1818 · 57 km away · intensity X
2,000 deathsSevere damage ($5–24M)tsunami
- 1847
Jalisco,Oaxaca,Michoacan
2 Oct 1847 · 237 km away · intensity IX
58 deathsSevere damage ($5–24M)
- 1875M7.5
San Cristobal De La Barranca
11 Feb 1875 · 243 km away
25 deathsModerate damage ($1–5M)
- 1911M7.6
Colima, Jalisco, Mexico City
7 Jun 1911 · 183 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1900M7.3
Mexico
20 Jan 1900 · 174 km away · intensity VIII
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.