Reviewed by USGSMexico110y ago
M7.2 earthquake 31 km S of San Francisco Cozoaltepec, Mexico
Saturday, December 29, 1917, 22:50:39 UTC · 15.533°N, 96.755°W
A magnitude 7.2 earthquake struck 31 km S of San Francisco Cozoaltepec, Mexico on Saturday, December 29, 1917, 22:50:39 UTC, at a depth of 20.0 km (shallow). It is the strongest earthquake within 300 km since an M7.5 on March 26, 1908.
- Magnitude
- 7.2
- Major · mw
- Depth
- 20 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 earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
888 kilotons of TNT
That is about 59 times the Hiroshima bomb. It released about 1,862 times the energy of a magnitude 5.0.
Tectonic setting
19 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
20 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 has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 10 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.82 km NW of Teojomulco, MexicoApril 15, 1907 · 130 km NW of this epicenter
- 7.56 km S of Copala, MexicoMarch 26, 1908 · 264 km NW of this epicenter
- 7.07 km N of Jesús Carranza, MexicoJune 2, 1916 · 287 km NE of this epicenter
- 6.699 km SE of Crucecita, MexicoNovember 21, 1916 · 135 km SE of this epicenter
- 6.54 km ESE of Santa María Jicaltepec, MexicoSeptember 24, 1910 · 162 km NW of this epicenter
- 6.329 km SSE of El Carrizal, MexicoJune 14, 1913 · 156 km E of this epicenter
- 6.3111 km S of San Mateo del Mar, MexicoOctober 19, 1917 · 209 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 31 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 53 recorded deaths. The most severe:
- 1870M7.9
Oaxaca,Zanaguia,San Francisco Ozolotepec
11 May 1870 · 51 km away
24 deathsSevere damage ($5–24M)tsunami
- 1787M8.6
San Marcos, Oaxaca
28 Mar 1787 · 215 km away · intensity IX
11 deathsSevere damage ($5–24M)tsunami
- 1882M7.5
Puebla,Huahuapan,Huamuxtitlan,Xalpatlahuac
19 Jul 1882 · 286 km away
7 deathsSevere damage ($5–24M)
- 1801M7.0
Oaxaca
5 Oct 1801 · 102 km away
7 deathsSevere damage ($5–24M)
- 1854M7.7
Veracruz,Oaxaca
5 May 1854 · 136 km away · intensity IX
4 deathsSevere damage ($5–24M)
- 1899M8.4
Guerrero-Oaxaca
24 Jan 1899 · 210 km away
Severe damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.