Reviewed by USGSGuatemala85y ago
M7.7 earthquake 26 km SSW of La Gomera, Guatemala
Thursday, August 6, 1942, 23:37:02 UTC · 13.863°N, 91.162°W
A magnitude 7.7 earthquake struck 26 km SSW of La Gomera, Guatemala on Thursday, August 6, 1942, 23:37:02 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.7 on September 7, 1915.
- Magnitude
- 7.7
- Major · mw
- Depth
- 35 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
5.4 megatons of TNT
That is about 355 times the Hiroshima bomb. It released about 11,220 times the energy of a magnitude 5.0.
Tectonic setting
61 km
from the nearest mapped plate boundary, between the Caribbean and North American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
35 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 M6.1 on August 8, 1942. 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 66 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.712 km NW of Chalatenango, El SalvadorSeptember 7, 1915 · 234 km E of this epicenter
- 7.34 km SSW of Puerto Madero, MexicoDecember 14, 1935 · 165 km NW of this epicenter
- 7.132 km NE of Chajul, GuatemalaFebruary 4, 1921 · 204 km N of this epicenter
- 7.0off the coast of Central AmericaJanuary 24, 1929 · 114 km SE of this epicenter
- 7.031 km SE of Champerico, GuatemalaApril 17, 1919 · 65 km W of this epicenter
- 6.94 km NNW of El Palmarcito, MexicoDecember 10, 1925 · 290 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 37 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 8,415 recorded deaths. The most severe:
- 1917M6.0
Guatemala City
26 Dec 1917 · 102 km away · intensity IX
2,650 deathsExtreme damage ($25M+)
- 1902M7.5
Quezaltenango, San Marcos
19 Apr 1902 · 23 km away
2,000 deathsSevere damage ($5–24M)tsunami
- 1854
San Salvador
14 Apr 1854 · 212 km away
1,000 deathsExtreme damage ($25M+)
- 1873
Santa Tomas, San Vicente
4 Mar 1873 · 221 km away
800 deathsExtreme damage ($25M+)
- 1773
St. Jago
3 Jun 1773 · 96 km away
600 deathsExtreme damage ($25M+)tsunami
- 1936
San Vicente
19 Dec 1936 · 276 km away
400 deaths
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.