Reviewed by USGSPanama100y ago
M6.7 earthquake 260 km SSW of Arenas, Panama
Saturday, August 20, 1927, 23:54:31 UTC · 5.286°N, 81.949°W
A magnitude 6.7 earthquake struck 260 km SSW of Arenas, Panama on Saturday, August 20, 1927, 23:54:31 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M7.2 on January 20, 1904.
- Magnitude
- 6.7
- Strong · mw
- Depth
- 10 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 earthquakeDashed circle: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
175 kilotons of TNT
That is about 12 times the Hiroshima bomb. It released about 367 times the energy of a magnitude 5.0.
Tectonic setting
103 km
from the nearest mapped plate boundary, between the Cocos and Nazca plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
10 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 lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M5.8 on August 21, 1927. 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 9 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.245 km SW of Quebrada de Piedra, PanamaJanuary 20, 1904 · 280 km N of this epicenter
- 6.697 km SSE of Burica, PanamaAugust 10, 1927 · 226 km N of this epicenter
- 6.5208 km S of Cambutal, PanamaDecember 2, 1904 · 157 km E of this epicenter
- 6.3192 km S of Burica, PanamaSeptember 24, 1920 · 135 km NW of this epicenter
- 6.275 km SSE of Pedasí, PanamaJune 30, 1917 · 289 km NE of this epicenter
- 6.1136 km S of Burica, PanamaMarch 9, 1927 · 190 km NW of this epicenter
- 6.0135 km SSE of Burica, PanamaOctober 25, 1921 · 186 km N of this epicenter
- 6.058 km SSW of Río Grande, PanamaJune 27, 1917 · 220 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1913M6.7
Azuero Peninsula
2 Oct 1913 · 251 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.