Reviewed by USGSNicaragua109y ago
M6.4 earthquake 144 km SW of Masachapa, Nicaragua
Wednesday, July 31, 1918, 14:37:10 UTC · 10.876°N, 87.462°W
A magnitude 6.4 earthquake struck 144 km SW of Masachapa, Nicaragua on Wednesday, July 31, 1918, 14:37:10 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.3 on February 27, 1916.
- Magnitude
- 6.4
- Strong · mw
- Depth
- 15 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
60 kilotons of TNT
That is about 4 times the Hiroshima bomb. It released about 126 times the energy of a magnitude 5.0.
Tectonic setting
17 km
from the nearest mapped plate boundary, between the Caribbean and Cocos 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 11 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.392 km SW of San Juan del Sur, NicaraguaDecember 30, 1907 · 108 km E of this epicenter
- 7.3204 km WSW of Sámara, Costa RicaFebruary 27, 1916 · 159 km S of this epicenter
- 7.2116 km SW of Corinto, NicaraguaJuly 1, 1907 · 97 km NW of this epicenter
- 7.0off the coast of Central AmericaAugust 16, 1909 · 283 km W of this epicenter
- 6.718 km WSW of Nicoya, Costa RicaJanuary 20, 1905 · 221 km SE of this epicenter
- 6.4177 km SSW of Puerto El Triunfo, El SalvadorJanuary 15, 1913 · 221 km NW 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. The most severe:
- 1885
Leon,Chinandega,Managua
12 Oct 1885 · 174 km away · intensity IX
Severe damage ($5–24M)
- 1898M7.9
Leon, Chinandega, Managua
29 Apr 1898 · 203 km away · intensity VIII
Moderate damage ($1–5M)
- 1844M7.4
Rivas, Greytown
May 1844 · 293 km away
Moderate damage ($1–5M)tsunami
- 1870
Leon
18 Jun 1870 · 194 km away
Moderate damage ($1–5M)
- 1881
San Juan Del Sur,Chinandega,Managua
29 Apr 1881 · 145 km away
Moderate damage ($1–5M)
- 1901M7.0
Nicaragua
8 Oct 1901 · 106 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.