Google Earth snapshot shows extent of Earthquake swarm in Chile
A snapshot of the earthquake damaged Chile shows us just how active the earthquake storm has been in the last week. The yellow dots shows earthquakes that happened in the past week. Just today there already were about 20 earthquakes in Chile above 4magnitude and Chile continues to shake.
There are now over 723 deaths in Chile because of the earthquake that struck this weekend. Authorities say about 60 people died when a 14 story building collapsed but they are still pulling out survivors.
As we wrote this another earthquake that’s part of the earthquake swarm hit Chile, this one was a 5.2 magnitude.
Thanks. It’s good to get information without the extras.
Thanks for the information. I’m sure glad I don’t live there!
“There’s a Whole lotta shakin’ goin’ on …”
Story compiled by Tom Dennen
Your comment bears out the following:
“The earth’s rotation acts on these (polar) unsymmetrically deposited (ice and snow) masses and produces centrifugal momentum that is transmitted to the rigid crust of the earth. The constantly increasing centrifugal momentum produced this way will, when it reaches a certain point, produce a movement of the earth’s crust over the earth’s body, and this will displace the polar regions towars the equator … Their ponderous weight pushes against the crust and this immense pressure, combined with the greater incline in the earth’s tilt [another changing factor of the orbital geometry] forces the (entire) crust to shift …” Albert Einstein, 1953.
Because the planet earth is a closed ecosystem, the amount of ice that accumulates on the poles reaches its maxmum weight every thirteen thousand years at which point severe geological disturbances occur, starting with earthquake swarms and tectonic plate shifts and ending with the entire crust’s displacement.
Earthquakes today are caused mostly by rupture or geological faults, volcanic activity, landslides, mine blasts but also by nuclear experiments.
We should be melting the poles.
Strong aftershocks can be associated with major temblors, even weeks or years after the main event. But they are primarily felt in the first 24 to 48 hours, and more should be expected.
“A large, vigorous aftershock sequence can be expected from this earthquake,” warns the U.S. Geological Survey. There have already been a number of aftershocks to hit Chile since the devastating 8.8 magnitude quake that struck early Saturday, the largest registering at magnitude 6.9, according to the USGS.
In the 2 1/2 hours following the 90-second quake, the U.S. Geological Survey reported 11 aftershocks, of which five measured 6.0 or above.
“Aftershocks are earthquakes,” said Carrieann Bedwell, geophysicist with the U.S. Geological Survey (USGS) and the National Earthquake Information Center (NEIC). “When there’s a large earthquake some like to say aftershocks occur because of a readjusting of the fault itself; it continually readjusts because it did have such a large energy release,” Bedwell said.
The shocks are primarily felt in the first 24 to 48 hours, but can come days, weeks, or even years later. Eight days after the earthquake that devastated the Haiti in January, a 6.1-magnitude quake hit the island nation — a strong aftershock associated with the major temblor, even though it was more than a week later.
“The aftershock refers to an earthquake that is close to the epicenter or within the rupture zone of a large earthquake, in that case the Haiti region where the 7.0 earthquake happened,” Bedwell said. Scientists define the rupture zone as the area in which energy was released from a major earthquake.
To tease out whether the shaking is considered an aftershock or a new quake, scientists also look at the depth where the new shaking started. In the case of the Haiti quake and aftershock, both were shallow, occurring just below the surface.
“That’s another parameter we look at when we are determining whether this is an aftershock to a large earthquake or not,” Bedwell said.
For the purposes of calculating other variables, the default is 10 kilometers, or 6.2 miles, below the surface. That’s why this depth is reported for both the major earthquake and its aftershock.
“Depth is the hardest thing to actually determine on shallow earthquakes,” said Don Blakeman, a geophysicist at the USGS and NEIC. “We have seismometer stations all over the world, but they are basically at the surface. We don’t have any that are at depth. Most of the seismometers are no deeper than 200 or 300 feet.”
He added, “It’s a big deal to drill 10 kilometers,” in order to insert a seismometer. “We can look at the recording of each of the waves at each station and even though we can’t come up with an exact number we can see by the character of the waves that it’s a shallow quake,” Blakeman said.
A shallow quake also means energy gets released very close to the surface, which can cause violent ground-shaking.
Even though aftershocks are usually expected, they can still take scientists and survivors by surprise.
“Aftershocks are unpredictable,” Bedwell told LiveScience. “We can predict that they are going to happen, but in terms of getting time and magnitude, that is unpredictable.”
LiveScience.com also contributed to this report.
what a lengthy and in depth article but full of useful information