Thursday, 12 April 2012

Earthquake Mexico 12 April 2012

6.9 quake in Mexico follows on heels of Indonesia tremor


2 very strong EXTREMELY dangerous earthquakes in the Gulf of California

Last update: April 12, 2012 at 8:09 am by By 
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Earthquake overview : A very strong ridge earthquake has hit the sea floor of the Gulf of California. The shaking will be extended onto the coastal areas like the Mexican continent and Baja California peninsula
“I have Felt it” Reports –> see below + Let us know “how you have felt this earthquake”
To read the full story as it happened, we advise our readers to start at the lower part of the page (earthquake data).
Check also our Mexico-only earthquake list
Keep this page open or return regularly as we will be back with more details when they become available
- USGS has calculated that 3000 people will have experienced a very strong shaking and that 105,000 have experienced a strong shaking. Both these areas are at risk for eventual damage, especially because 9 minutes earlier another very strong earthquake struck the same area.
- The Mexican Servico Sismologico Nacional reports a magnitude of 6.8 with an epicenter below land. These makes this earthquake the most dangerous in 24 hours !
- Although it is a ridge earthquake, the epicenter of the M6.9 quake looks to be very close to the coast which makes this earthquake (the second very strong in a matter of 9 minutes) EXTREMELY DANGEROUS for shaking damage and fatalities. Let us hope that we are too pessimistic here. The kind of shaking will depend on the focal mechanism
- Following calculations by the USGS (providing that the earthquake data are correct) a MMI VII will have been experienced on the Baja California peninsula ! This means dangerous for the coastal areas experiencing this kind of shaking.
- The whole North American continent is currently moving in such a way that the earthquakes of the last 12 hours are somehow related (Mexico Sur, Mexico Gulf of California, Utah, Oregon) . Scientists will have a lot of work in examining eventual relationships however there is no certainty at all that a relation would exist (at least for a couple of these earthquakes)
- We are talking in this case about a Ridge earthquake, this means 2 separating plates who are hanging and suddenly get away from each other. Ridge earthquakes are typical for Middle Ocean locations
- The earthquake struck just after midnight
- We are currently collecting data

Earthquakes shake Gulf of California



CNN) -- A pair of strong earthquakes rocked Mexico's Gulf of California only minutes apart early Thursday, the U.S. Geological Survey reported.

The quakes -- magnitude 6.9 and 6.2 -- were centered about 85 miles northeast of Guerrero Negro in the Mexican state of Baja California, or 325 miles south-southwest of Phoenix in the United States. Both epicenters were shallow, a little more than six miles underground.
No tsunami warnings were issued and there were no immediate reports of damage, but people as far north as Tucson, Arizona, reported feeling them.
The temblors were recorded at 12:16 a.m. and 12:06 a.m. local time (3:16 a.m. and 3;06 a.m. ET).





Associated Press, Mexico City | Thu, 04/12/2012 7:47 AM
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People begin returning to a building that was evacuated after an earthquake was felt in Mexico City, Mexico, on Wednesday. The U.S. Geological Survey reported a preliminary reading of 7.0 magnitude for the quake, which it said was centered 238 miles (384 kilometers) west-southwest of Mexico City and 88 miles (143 kilometers) northwest of the Pacific resort of Zihuantanejo. (AP/Dario Lopez-Mills) People begin returning to a building that was evacuated after an earthquake was felt in Mexico City, Mexico, on Wednesday. The U.S. Geological Survey reported a preliminary reading of 7.0 magnitude for the quake, which it said was centered 238 miles (384 kilometers) west-southwest of Mexico City and 88 miles (143 kilometers) northwest of the Pacific resort of Zihuantanejo. (AP/Dario Lopez-Mills)
A strong earthquake struck a sparsely populated area in the mountains of western Mexico on Wednesday, and caused tall buildings to sway more than 200 miles away in Mexico City. 
People evacuated some buildings in the capital, but the city government said helicopter flights detected no signs of damage.
Authorities in Michoacan state, where the tremor was centered, also had no immediate reports of damage.
The U.S. Geological Survey initially reported a preliminary reading of 7.0 magnitude for the quake, but later downgraded it to 6.5.
A quake of that magnitude is capable of producing severe damage in an urban area, but this one occurred about 41 miles (65.6 kilometers) below the surface and a tremor's power to cause damage is often dissipated when it is so deep.
The USGS said the tremor was centered in Michoacan state 238 miles (384 kilometers) west-southwest of Mexico City and 88 miles (143 kilometers) northwest of the Pacific resort of Zihuantanejo.
Manuel Ortiz Rosete, the Michoacan state civil protection director, said no damage had been reported in major cities and coastal communities of the state.
Wednesday's tremor was the latest in a series of strong shakes to hit Mexico City since a powerful 7.4-magnitude quake hit southern Mexico three weeks ago, but this was not an aftershock of that one , USGS geophysicist Dale Grant said.
"It's a different earthquake. We are calling it an individual earthquake," Grant said. "There's a potential for aftershocks."
Last month's big earthquake was felt strongly in the nation's capital, and it damaged hundreds of homes and killed at least two people near the border between Guerrero and Oaxaca states. Mexico's seismological service said that quake has been followed by close to 400 aftershocks, including one of magnitude 6.0.
A quake alert application for Blackberrys that Mexico City's government touted last week did not work Tuesday. Mexico City Mayor Marcelo Ebrard said the alert system has been working for quakes centered in two southern states and will begin to work for any tremors in Michoacan in the next few days.