Magnitude 6.0 - COSTA RICA

[Shiloh]

Source: http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0003et0.php

Magnitude 6.0 - COSTA RICA
2011 May 13 22:47:55 UTC


Earthquake Details

* This event has been reviewed by a seismologist.

Magnitude 6.0
Date-Time

* Friday, May 13, 2011 at 22:47:55 UTC
* Friday, May 13, 2011 at 04:47:55 PM at epicenter

Location 10.105?N, 84.261?W
Depth 70 km (43.5 miles)
Region COSTA RICA
Distances

* 25 km (16 miles) WNW (303?) from SAN JOSE, Costa Rica
* 126 km (78 miles) SSE (153?) from San Carlos, Nicaragua
* 137 km (85 miles) W (275?) from Limon, Costa Rica

Location Uncertainty horizontal +/- 16.5 km (10.3 miles); depth +/- 8.8 km (5.5 miles)
Parameters NST=376, Nph=381, Dmin=20 km, Rmss=1.23 sec, Gp=115?,
M-type=regional moment magnitude (Mw), Version=9
Source

* U.S. Geological Survey, National Earthquake Information Center:
World Data Center for Seismology, Denver

Event ID usc0003et0

 

[Tonka]

Re: Magnitude 6.0 - COSTA RICA

http://www.nacion.com/2011-05-14/ElPais/NotaPrincipal/N14-SISMO.aspx
Spanish to English translation

COCO PLATE FAILURE OCCURRED 74 KILOMETERS
Quake depth of 6 ? Puriscal mitigate impacts
Distance where deformation occurred decreased force of destructive waves
Tremors are caused by plate failure usually does not cause aftershocks

The earthquake of 6 degrees on the Richter scale that struck the country yesterday was caused by an abnormality in Cocos plate at a depth so great that it caused further damage to the surface.


VIDEO


Swarm rattled the area in 1990
Cleft Coco plate was reactivated and caused seismic
tremor revived fears puriscale?os 21 years ago
Chaos in San Jos? and Alajuela lasted little
more than 100,000 call attempts collapsed ICE network
ANNEXES

A rare earthquake: computer graphics with details of the earthquake of aller.
The movement originated at 4:47 pm, 6 km north of Puriscal. The National Volcanological and Seismological Observatory (OVSICORI) initially reported a magnitude of 5.9 degrees and located 65 km deep into the Earth's mantle.

At 8:40 pm, the Earthquake Engineering Laboratory at the University of Costa Rica you upgraded to 6 ? and a depth of 74 km.

Javier Pacheco, OVSICORI seismologist, said the phenomenon of subduction (sliding) Cocos plate beneath the Caribbean plate causes deformation Coco. One of these deformations or failures were off yesterday and caused the quake.

Even the tremor occurred below the depth where the crash happens plate subduction (40 km).

Pacheo said: "The depth helped because it is too distant, the waves are attenuated and will not arrive with equal force to the surface."

Guillermo Alvarado, a seismologist and volcanologist National Seismic Network, explained that the quake would have been more superficial (such as Cinchona, 6.2 degrees and 5 km deep), the effects would have been "very damaging."

That was what happened in Puriscal the December 22, 1990, when an earthquake measuring 5.7 degrees to 10 km depth, caused by local failure, damaged dozens of homes, one person died in Alajuela.

With regard to intraplate earthquakes, like yesterday, the OVSICORI argues that usually do not have replicas, at least in Costa Rica.

Alvarado said that although the quake was reported in Puriscal, feeling that he was "very strong" spread to nearby places like Greece Turrucares or Alajuela.

He added that the perception of people is that there were two earthquakes in quick succession, but the right thing is that it was one with two waves, the second, much stronger.

He explained that an earthquake at that depth because a wave that spreads like a funnel even at distant locations, as happens when you throw a stone into a lake.

So citizens reported that they felt strongly in places as distant as San Jose, Santa Ana, Perez Zeledon, downtown Alajuela, San Carlos, Carrizal, Naranjo, Heredia downtown, downtown Cartago, Turrialba, Batan, Nandayure, Ca?as, Puntarenas Palmar . Collaborated David Delgado, Jairo Villegas, Michelle Soto, Alejandro Arley, Amy Marvin Ross and Gamboa.