Reviewed by USGSMexico99y ago
M7.4 earthquake 8 km ENE of Santiago Xanica, Mexico
Thursday, March 22, 1928, 04:17:04 UTC · 16.037°N, 96.155°W
A magnitude 7.4 earthquake struck 8 km ENE of Santiago Xanica, Mexico on Thursday, March 22, 1928, 04:17:04 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on April 15, 1907.
- 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
2.2 megatons of TNT
That is about 145 times the Hiroshima bomb. It released about 4,571 times the energy of a magnitude 5.0.
Tectonic setting
75 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 2 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.5 on April 17, 1928. 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 16 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 · 133 km NW of this epicenter
- 7.2127 km SW of La Esperanza (El Zapotal), MexicoMarch 30, 1914 · 283 km SE of this epicenter
- 7.231 km S of San Francisco Cozoaltepec, MexicoDecember 29, 1917 · 85 km SW of this epicenter
- 7.07 km N of Jesús Carranza, MexicoJune 2, 1916 · 203 km NE of this epicenter
- 6.699 km SE of Crucecita, MexicoNovember 21, 1916 · 127 km SE of this epicenter
- 6.54 km ESE of Santa María Jicaltepec, MexicoSeptember 24, 1910 · 201 km W of this epicenter
- 6.47 km W of San Felipe Tejalápam, MexicoApril 19, 1920 · 144 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 32 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 57 recorded deaths. The most severe:
- 1870M7.9
Oaxaca,Zanaguia,San Francisco Ozolotepec
11 May 1870 · 73 km away
24 deathsSevere damage ($5–24M)tsunami
- 1787M8.6
San Marcos, Oaxaca
28 Mar 1787 · 256 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 · 19 km away
7 deathsSevere damage ($5–24M)
- 1854M7.7
Veracruz,Oaxaca
5 May 1854 · 169 km away · intensity IX
4 deathsSevere damage ($5–24M)
- 1928M7.7
Oaxaca
17 Jun 1928 · 94 km away
4 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.