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When the Earth Shakes

On Saturday morning miles off the coast of Chile and 22 miles under the surface of the earth there was a shift in the plates that form the boundaries of our planet. This shift released some pent up energy, much like snapping a global size rubber band. That energy was felt as an earthquake in Chile.

The death toll is not as high as in Haiti and there are several reasons for that, which form the substance of this blog. Understanding earthquakes means taking a look at our planet and seeing more than the mountains and the planes…but the crustal plates. This tectonic understanding is important because every corner of the earth can be impacted by earthquakes. Likewise, the psyche and economy of any country can be stressed greatly when a disaster of this nature occurs.

I have relatives in Maui who were awakened at 6AM by the Tsunami warning sirens. These are much like tornado sirens in the Midwest. They warn of potential danger and prompt folks to seek some sort of safe place. In the case of a tsunami that would be higher ground.

A tsunami is not a huge wave that breaks offshore and levels buildings with its immense height. It is more like a flash flood that comes in from the ocean side and keeps coming for quite some time. There are amazing videos and helpful web sites that have sprung up after a devastating Indonesian Tsunami several years ago. One that focuses on the science and understanding is by National Geographic.

http://news.nationalgeographic.com/news/2007/04/070402-tsunami.html

The Pacific Tsunami Museum in Hilo, Hawaii is also a great starting place.
http://www.tsunami.org/

The quake in Chile on Saturday was not the largest ever recorded. A Magnitude 8.8 is very large but the largest ever recorded did occur in Chile in 1960. That quake measured 9.5 on the Richter scale. That scale is explained at this web site with an in- depth discussion of the math behind the scale.
http://www.seismo.unr.edu/ftp/pub/louie/class/100/magnitude.html

There are some key difference between the earthquake in Haiti and the quake in Chile. These are explained in detail on this site:
http://online.wsj.com/article/SB10001424052748704089904575094013194396670.html?mod=WSJ-hpp-MIDDLENexttoWhatsNewsTop

There are about 10,000 earthquakes in the Southern California in any given year. There are over 500,000 quakes worldwide. Some are mild enough not to be felt. But many cause damage. A great site for facts on earthquakes is the USGS site.
http://earthquake.usgs.gov/learn/facts.php

I would begin any earthquake discussion, lesson or unit with a short lecture burst on tectonic plates. There are several free PowerPoint sets online to help.
http://science.pppst.com/platetectonics.html

Next, I would center on the strength of quakes and how we measure them.
http://tremor.nmt.edu/faq/how.html

Finally I would center the lesson on great quakes scientists have studied in the past. This site gives you a map and lots of facts.
http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php

Finally, for those who really want to explore the science of earthquakes you can build your own seismograph or seismometer:
http://www.ehow.com/how_4563662_build-seismograph.html
 
http://pbskids.org/zoom/activities/sci/seismometer.html
 
The RAFT center in California has several activities that are great hands on simple builds for science classes on earthquakes. Scroll through the activities to the “shake table” or the “your Room in an Earthquake”.
http://www.raft.net/index.php?pg=idearesults&dtl=ESS&pgnumber=5&qty=20

So, while waiting for the next big shake, and it will come as we live on a restless planet, you have a little time to beef up your earth science with some earthquake science.

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