Reviewed by USGSPanama35y ago
M4.0 earthquake 35 km WSW of Barranco Adentro, Panama
Monday, April 29, 1991, 22:48:38 UTC · 9.370°N, 83.010°W
A magnitude 4.0 earthquake struck 35 km WSW of Barranco Adentro, Panama on Monday, April 29, 1991, 22:48:38 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 4.0
- Light · mb
- 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
15 tons of TNT
That is about 1/998 of the Hiroshima bomb. A magnitude 5.0 releases about 32 times more energy.
Tectonic setting
50 km
from the nearest mapped plate boundary, between the Panama and Caribbean plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
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 50 km
USGS lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.7 on May 27, 1991. 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 229 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.634 km S of Limón, Costa RicaApril 22, 1991 · 36 km N of this epicenter
- 7.64 km WNW of Atenas, Costa RicaDecember 21, 1939 · 168 km NW of this epicenter
- 7.5Costa RicaOctober 5, 1950 · 255 km NW of this epicenter
- 7.544 km ESE of Burica, PanamaJuly 18, 1934 · 177 km S of this epicenter
- 7.570 km WSW of Golfito, Costa RicaDecember 5, 1941 · 138 km SW of this epicenter
- 7.37 km SSE of Puntarenas, Costa RicaMarch 25, 1990 · 206 km W of this epicenter
- 7.353 km SSE of Quepos, Costa RicaDecember 20, 1904 · 122 km W 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 871 recorded deaths. The most severe:
- 1910M6.4
Cartago, San Jose
4 May 1910 · 129 km away
700 deathsSevere damage ($5–24M)
- 1991M7.6
Limon, Pandora; Panama
22 Apr 1991 · 36 km away · intensity X
90 deaths$510 million damagetsunami
- 1952
Costa Rica
30 Dec 1952 · 117 km away
29 deaths
- 1973M6.5
Tilaran, Arenal, Rio Chiquito
14 Apr 1973 · 241 km away
26 deathsUnder $1 million damage
- 1955M5.8
Costa Rica
1 Sep 1955 · 178 km away
10 deathsModerate damage ($1–5M)
- 1941M7.6
Costa Rica-Panama
5 Dec 1941 · 77 km away · intensity IV
6 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.