Large Earthquake off El Salvador

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Massive earthquake far out of the El Salvador coast

Last update: August 27, 2012 at 9:17 pm by By

Massive earthquake along the coast of El Salvador ??
Preliminary Magnitude and depth : M7.4 @ 52.9 km
Approx. 125 km out of the coast
NOAA reports : BASED ON THE EARTHQUAKE MAGNITUDE… LOCATION AND HISTORIC TSUNAMI RECORDS A DAMAGING TSUNAMI IS NOT EXPECTED ALONG THE CALIFORNIA/ OREGON/ WASHINGTON/ BRITISH COLUMBIA AND ALASKA COASTS.
Max. wave height along the Central America coast : 0.1 meter or NO danger
NO people are living within a radius of 100 km
Important Update : Confusion in seismic land : The 3 main international agencies are reporting very conflicting numbers. Geofon reports a Magnitude of M6.6 and EMSC only a M5.2
Our attention was attracted to the fact that we had very few readers from Central America which is opposite on what we see otherwise. Hard to believe that a massive quake at 50 km at 125 km out of the coasr would not be felt by people on land.
The central american agencies are simply not reporting an earthquake at the time of occurrence. This data looks more and more being a hoax
Update : All the agencies are now showing 7+ magnitudes for the El Salvador earthquake, EMSC and Geofon even at shallower depths
Update 05:40 UTC : We are still confused about this massive earthquake as the local agencies still do not list it including El Salvador’s SNET and as we had no abnormal number of Central American readers in the website
(Almost) Final update 06:47 : The mystery has finally been solved. SNET (El Salvador) has also listed the earthquake as an M6.7 earthquake at a depth of 50 km but more than 200 km out of the coast. Additionally, the hypocenter of the earthquake was located in the oceanic plate and not in the North American plate. This event was in other words an intra-plate event and not a subduction earthquake like most of the earthquakes are in the area.
Update 07:17 : A couple of 5+ aftershocks occurred in the greater epicenter area. USGS has located the epicenter of all events in the subduction zone below the continental plate while snet was putting it more into the ocean.
– To make the confusion complate, also USGS has now updated the hypocenter from a +50 km to a depth of 20.3 km.
– Ineter Nicaragua is reporting the mainshock as a Mc5.9!
Update 09:19 UTC : A new strong aftershock struck closer to the El Salvador coast.
Update 12:14 UTC : Tsunami calculations greatly depend upon the underlying earthquake parameters. In a first tsunami report GDACS based their calculations on a depth of 52.3 km (data according USGS preliminary report). A max. waveheight of 0.1 m was the result. After that USGS changed the depth of the hypocenter to 20.3 km a totally different calculation resulted in a max. wave pattern of 0.5 meter, a huge difference. As it was evening in the epicenter area, we guess that almost nobody would have seen the waves. This event is a reminder that seismology is not an exact science and has still a quiet important error margin.

Image courtesy GDACS

from:    http://earthquake-report.com/2012/08/27/major-earthquakes-list-august-27-2012/