Friday, March 11, 2011

The Earth is Restless

I am sure you have all heard about the devastating earthquake that hit Japan early today and the subsequent tsumani warnings that have gone up across the Pacific Ocean.  At the time of writing this, the tsumani has not yet hit the west coast of the U.S. so it remains to be seen what the outcome from that will be.  I do want to let the people that are dealing with this that you are in my thoughts and I am hopeful that you are safe and well. I am positive that sentiment would be the same for all of the staff at SSSA, ASA and CSSA.

This was a big earthquake - a magnitude of 8.9 on the Richter scale. The biggest one Japan has ever recorded and they are arguably the best equipped to handle such things from the point of building design and engineering. The earthquake was caused by a shift in the Earth's plates, which released a tremendous amount of energy. When earthquakes occur in the ocean, the displacement of the Earth's crust and the release of that energy can cause havoc. This is seen in the tsunami that is making its way across the ocean after causing extensive damage in Japan. If you don't know about tsunamis, they move fast (up to 600 mph in the open ocean), but if you are in  deep open water you may not notice it. As the energy wave moves through the open water there is often minimal evidence of it on the surface of the ocean. However, when that wave of energy wave starts hitting shallow water and the velocity at the bottom of the wave slows with the topography, it forces the wave of water to rise as it hits the coast.  This is why boats will exit the harbor and get out to sea if they possibly can prior to a tsunami hitting the coast. (An admittedly simplified explanation, but if interested look it up!  Also take a look at the early warning system of buoys that the U.S. has in place in the PacificOcean, which were being used today to predict the impact on Hawaii and the west coast of North America.)

If you have seen any of the footage, you may also have seen the very large whirlpool that was caused near the site of the eathquake due to the differing directions of  seismic wave action and likely the bulging or opening up of the Earth's crust.  All very interesting phenomenon if you aren't in the area of the earthquake or path of the tsunami. 

From a geoscience perspective the shifting of the Earth's plates (plate tectonics) has always fascinated me, in fact I considered geology as a major due to my interest in it.  As much as the shifting of the plates is a natural event, we have seen over the last few years or so many of these events have profound effects on human population.  From the tsunami in the Indian Ocean in 2004, to the earthquake in Haiti, to the volcano in Iceland last year that shut down air traffic across Europe, to the earthquake in Chile and now this.  It is thought that the magnitude of this latest earthquake will cause another change in the tilt of the Earth's axis, much like the eathquake in Chile caused.

The Earth is restless.  From a human standpoint it is hard to watch and make sense of the devastation. From a purely scientific standpoint, it is indeed interesting to observe, learn and try to understand.

2 comments:

  1. Dawn:
    The earth is restless indeed. I have been watching the news from Christchurch with keen interest as I was just there a few months ago when a 5.0 magnitude quake hit. I know people who have been affected by the latest one. The phenomenon of liquefaction was apparent in New Zealand and film footage showed the inland swirls of liquid earth - not unlike the whirlpools of water off Japan. To my knowledge we have not been affected yet on the east coast of Australia by the Japanese quake.

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  2. John brings up a good point about liquefaction. John, if you have some video that you can post links to please do so that people can see what it looks like.

    I also saw a video posted by American James MacWhyte in Japan of a town being washed away in the tsunami last week. The video is 6 minutes long - watch the whole thing - amazing how what starts out to be not much water becomes a river that carries away buildings.
    http://bit.ly/dYi9u5

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