Reviewed by USGSCosta Rica14y ago
M4.3 earthquake 34 km WSW of Santa Cruz, Costa Rica
Sunday, September 23, 2012, 21:35:05 UTC · 10.192°N, 85.890°W
A magnitude 4.3 earthquake struck 34 km WSW of Santa Cruz, Costa Rica on Sunday, September 23, 2012, 21:35:05 UTC, at a depth of 44.0 km (shallow).
- Magnitude
- 4.3
- Light · mb
- Depth
- 44 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
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
Tectonic setting
26 km
from the nearest mapped plate boundary, between the Sunda and Burma plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
44 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.3 on October 10, 2012. 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 435 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.783 km SSW of Corinto, NicaraguaSeptember 2, 1992 · 234 km NW of this epicenter
- 7.611 km ENE of Hojancha, Costa RicaSeptember 5, 2012 · 64 km E of this epicenter
- 7.64 km WNW of Atenas, Costa RicaDecember 21, 1939 · 163 km E of this epicenter
- 7.5Costa RicaOctober 5, 1950 · 98 km E of this epicenter
- 7.37 km SSE of Puntarenas, Costa RicaMarch 25, 1990 · 122 km E of this epicenter
- 7.392 km SW of San Juan del Sur, NicaraguaDecember 30, 1907 · 85 km NW of this epicenter
- 7.353 km SSE of Quepos, Costa RicaDecember 20, 1904 · 244 km SE of this epicenter
- 7.3204 km WSW of Sámara, Costa RicaFebruary 27, 1916 · 179 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 48 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 11,981 recorded deaths. The most severe:
- 1972M6.2
Managua
23 Dec 1972 · 247 km away
10,000 deaths$3.0 billion damage
- 1930
Managua
31 Mar 1930 · 215 km away
1,000 deaths$15 million damage
- 1910M6.4
Cartago, San Jose
4 May 1910 · 208 km away
700 deathsSevere damage ($5–24M)
- 1992M7.6
Masachapa; Costa Rica
2 Sep 1992 · 237 km away
170 deaths$30 million damagetsunami
- 1952
Costa Rica
30 Dec 1952 · 262 km away
29 deaths
- 1973M6.5
Tilaran, Arenal, Rio Chiquito
14 Apr 1973 · 135 km away
26 deathsUnder $1 million damage
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.