M7.6 earthquake 11 km ENE of Hojancha, Costa Rica

Wednesday, September 5, 2012, 14:42:07 UTC · 10.085°N, 85.315°W

A magnitude 7.6 earthquake struck 11 km ENE of Hojancha, Costa Rica on Wednesday, September 5, 2012, 14:42:07 UTC, at a depth of 35.0 km (shallow). USGS received 769 “Did You Feel It?” reports, with a maximum reported intensity of VIII (severe). It is the strongest earthquake within 300 km since an M7.7 on September 2, 1992.

Magnitude: 7.6; Major · mww
Depth: 35 km; Shallow
Felt reports: 769; Max intensity VIII
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

3.8 megatons of TNT

That is about 252 times the Hiroshima bomb. It released about 7,943 times the energy of a magnitude 5.0.

Tectonic setting

61 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

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

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Nicoya, Guanacaste, Costa Rica	VI · Strong	74	38 km
Santa Ana, San José, Costa Rica	V · Moderate	51	130 km
Managua, Managua, Nicaragua	IV · Light	36	253 km
Heredia, Heredia, Costa Rica	VI · Strong	29	135 km
San José, San José, Costa Rica	VI · Strong	29	140 km
San Felipe, San José, Costa Rica	V · Moderate	27	139 km
Santa Cruz, Guanacaste, Costa Rica	VII · Very strong	24	50 km
Alajuela, Alajuela, Costa Rica	VI · Strong	24	124 km
Escazú, San José, Costa Rica	V · Moderate	20	133 km
Sardinal, Guanacaste, Costa Rica	VII · Very strong	16	69 km
San Rafael Abajo, San José, Costa Rica	V · Moderate	16	122 km
Pital, Alajuela, Costa Rica	V · Moderate	15	125 km

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 37 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.7 on September 8, 2012. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 419 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 53 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 12,083 recorded deaths. The most severe:

1972M6.2
Managua
23 Dec 1972 · 271 km away
10,000 deaths$3.0 billion damage
1930
Managua
31 Mar 1930 · 244 km away
1,000 deaths$15 million damage
1910M6.4
Cartago, San Jose
4 May 1910 · 144 km away
700 deathsSevere damage ($5–24M)
1992M7.6
Masachapa; Costa Rica
2 Sep 1992 · 296 km away
170 deaths$30 million damagetsunami
1991M7.6
Limon, Pandora; Panama
22 Apr 1991 · 250 km away · intensity X
90 deaths$510 million damagetsunami
1952
Costa Rica
30 Dec 1952 · 200 km away
29 deaths

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers