Reviewed by USGSMexico89y ago
M6.6 earthquake 233 km SW of La Cruz de Loreto, Mexico
Friday, July 22, 1938, 07:48:11 UTC · 18.658°N, 107.164°W
A magnitude 6.6 earthquake struck 233 km SW of La Cruz de Loreto, Mexico on Friday, July 22, 1938, 07:48:11 UTC, at a depth of 20.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on November 30, 1934.
- Magnitude
- 6.6
- Strong · mw
- Depth
- 20 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
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
6 km
from the nearest mapped plate boundary, between the Rivera and Pacific 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 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 34 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.712 km NNE of La Central, MexicoJune 22, 1932 · 300 km E of this epicenter
- 7.0102 km SW of Barra de Navidad, MexicoNovember 30, 1934 · 197 km E of this epicenter
- 7.0166 km WSW of Corral del Risco (Punta de Mita), MexicoMay 9, 1905 · 201 km N of this epicenter
- 7.0Revilla Gigedo Islands regionDecember 17, 1905 · 152 km W of this epicenter
- 6.9211 km SW of José María Morelos, MexicoNovember 16, 1925 · 51 km SE of this epicenter
- 6.8256 km SW of La Cruz de Loreto, MexicoJanuary 2, 1931 · 34 km W of this epicenter
- 6.753 km SSW of El Colomo, MexicoDecember 13, 1933 · 284 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 75 recorded deaths. The most severe:
- 1932M7.7
Central
22 Jun 1932 · 300 km away
75 deathsSevere damage ($5–24M)tsunami
- 1900M7.3
Mexico
20 Jan 1900 · 272 km away · intensity VIII
Severe damage ($5–24M)tsunami
- 1934M7.0
Jalisco
30 Nov 1934 · 176 km away
Severe damage ($5–24M)tsunami
- 1875M7.4
Guadalajara, Mexico City
9 Mar 1875 · 282 km away
Moderate damage ($1–5M)tsunami
- 1925M7.0
S. Mexico
16 Nov 1925 · 25 km away
Moderate damage ($1–5M)tsunami
- 1900M6.9
Near Coast Of Jalisco
16 May 1900 · 272 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.