why were there so many earthquakes in 4 places at almost the same time?
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M$2 Answers
In short, its nothing out of the ordinary. The Earth experiences thousands of earthquakes each year due to the movement of tectonic plates which are underneath continental and oceanic crust. The plates slide past each other, or one plate is subducted beneath another one and the resulting pressure waves cause an earthquake. The action is driven by convection currents beneath the plates, in the molten part of the earth, or the mantle.
Over the last 10 years or so, the Earth has averaged over 1600 earthquakes per year that were magnitude 5 or larger. As a rule of thumb, for every magnitude you drop down, there are roughly ten times more earthquakes, to a certain extent. No one is sure exactly how far down this can be carried. Also, now that we have nearly instantaneous news, we find out about more of these quakes, even less severe ones, say below magnitude 4.0 to 6.0 (the closer to a population center a quake is, the more destructive it can be.. its not just the threshold of magnitude).
When we have several fairly large earthquakes causing devastation and making news within a short period of time, it seems related, but its likely coincidental. The epicenters of all of these quakes were 1,000's of miles apart and occurred along the boundaries of different tectonic plates. Future earthquakes can result after a major one, due to stresses incurred within a tectonic plate from the original earthquake. This usually happens when part of the plate breaks making two smaller plates. This can happen days or months after the original event and the resulting movement causes an earthquake.
I studied a lot of geology :)
http://www.newton.dep.anl.gov/askasci/gen99/gen99281.htm
http://earthquake.usgs.gov/earthquakes/
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M$
---quote--
Earthquakes occurring at the edges of tectonic plates can trigger events at a distance and much later in time, according to a team of researchers reporting in the journal Nature on January 31. These doublet earthquakes may hold an underestimated hazard, but may also shed light on earthquake dynamics.
---end of quote---
You can read further at the source.
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Sorry annelisle, but not at different tectonic plates; all the given events occurred at different plates!
the article discusses about two places on the Pacific plate near Japan
This question was asked before:
http://www.mahalo.com/answers/environment/why-so-many-earthquakes
wow 2100 readers!
I place again the link I used in my previous answer
http://earthquake.usgs.gov/learn/faq/?faqID=110
@pmoh7 The occurrence of earthquakes is a scientific phenomenon. There is no evidence to suggest otherwise. If you would like, please list a scientific source indicating that there has "never, ever, been anything like this". The higher the magnitude, the less likely a quake will occur, but the Earth still experiences many quakes per year with a magnitude higher than 5.0.
Furthermore, you start off by saying that you agree how this is nothing out of the ordinary, and then explain why you think this is out of the ordinary. All too often, religion uses the occurrence of scientific phenomenon to validate its various predictions. If not the earthquakes, it will be the flooding that we may experience this spring due to El Nino conditions. This does two things. It give the appearance that you are grasping at anything that will explain biblical predictions, and it lessens the respect that one might have for the organization you are affiliated with.
In terms of the occurrence of earthquakes, I agree that there is nothing out of the ordinary. Earthquakes have always been. However, history also shows that, in terms of the rapid succession of their occurrence and their heightening magnitude, there has never, ever, been anything like this. No one has been able to dispute this truth with any historical data; not just the the fact of their magnitude but the fact of their magnitude combining with such rapid succession of their happenings. Only biblical predictions show this was going to happen, and that when this begins to happen, it would only be the beginning of pangs...' for these things must first come to pass but the end is not yet'! These predictions are simply coming to pass. If this is so, watch out for the remaining stories unfold in the years following. You may no believe the predictions of the oldest book on earth, the Bible, but you certainly agree that if 1+1 is 2, then 2+2 is 4. If you do, here's what I have to say to you; these are not normal days. If the biblical predictions on these, like on many other issues are coming through (that is, 1+1 is 2), then get ready for the the remaining story (2+2 is 4!) I am alarmed at the simplicity by which people want to pacify their emotions, make content with naive explanations for what is happening to this world, and just bury their head in sand; hoping for safety but do nothing to prepare their life after now, should they fall victim to the death sentence of an earthquake. Look around you; one earthquake may be getting too close to you, and lets face it, the mourners might soon come for your neighbour or even you. Close your eyes and call this scare-tactics, and that would have made you pretty much like the proverbial ostrich that buried it's head in sand, while hoping for safety in the face of a sandstorm.This world will never be the same again. Be prapared.