Posted on 06/02/2015 3:27:40 PM PDT by JimSEA
Fact or Fiction?
broken earth cartoon FACT: Earthquakes are sudden rolling or shaking events caused by movement under the Earth’s surface.
An earthquake is the ground shaking caused by a sudden slip on a fault. Stresses in the earth's outer layer push the sides of the fault together. Stress builds up and the rocks slip suddenly, releasing energy in waves that travel through the earth's crust and cause the shaking that we feel during an earthquake.
Faults are caused by the tectonic plates grinding and scraping against each other as they continuously and slowly move. In California, for example, there are two plates - the Pacific Plate (which extends from western California to Japan, including much of the Pacific Ocean floor) and the North American Plate (which is most of the North American continent and parts of the Atlantic Ocean). The Pacific Plate moves northwestward past the North American Plate along the San Andreas Fault at a rate of about two inches per year.
Parts of the San Andreas Fault system adapt to this movement by constant "creep" resulting in many tiny shocks and a few moderate earth tremors. In other parts, strain can build up for hundreds of years, producing great earthquakes when it finally releases. Large and small earthquakes can also occur on faults not previously recognized; recent earthquakes in Alabama and Virginia are good examples.
(Excerpt) Read more at earthquake.usgs.gov ...
Her claim to fame was playing Pam Ewing on “Dallas.”
Had to look it up. A thrust fault can shake things up more than a slip/slide because the ground is moving up. There are signs of several long past thrust fault zones at the Oregon coast (relatively small ones).
“Victoria Principal (born January 3, 1950)[1] is an American actress, author and businesswoman best known for her role as Pamela Barnes Ewing on the CBS nighttime soap opera Dallas from 1978 to 1987.”
http://en.wikipedia.org/wiki/Victoria_Principal
I nearly completed a BS (4-yr) degree in Geology. Came one field course away.
I have always regretted not taking geology for a degree. The lifetime interest began when I was growing up and went to work in Superior, AZ. I got a fairly good understanding of mine geology and since plate tectonics came along in the late sixties, I’ve read a lot. Now if I could just remember what I read. ;-)
Was not the total series of the New Madrid earthquakes (there were 4 or 5 large ones) larger than any known decade of the San Andreas?
Thanks for posting those.
I chose Geology because I fascinated by the rocky outcrops I saw as a kid on our family’s annual rail trip from New York City to Tennessee to visit relatives there. I wanted to know how they came to be. Same with the Great Smoky Mountains that my 1/4-Cheokkee grandfather there would always take us to see. Also because it combined many of the other sciences I was really interested in: physics, paleontology (fossils), astronomy, chemistry...
“The 1811–1812 New Madrid earthquakes were an intense intraplate earthquake series beginning with an initial pair of very large earthquakes on December 16, 1811. They remain the most powerful earthquakes to hit the contiguous United States east of the Rocky Mountains in recorded history.[1] They, as well as the seismic zone of their occurrence, were named for the Mississippi River town of New Madrid, then part of the Louisiana Territory, now within Missouri.
There are estimates that the earthquakes were felt strongly over roughly 130,000 square kilometers (50,000 sq mi), and moderately across nearly 3 million square kilometers (1 million square miles). The 1906 San Francisco earthquake, by comparison, was felt moderately over roughly 16,000 km2 (6,200 sq mi).”
http://en.wikipedia.org/wiki/1811%E2%80%9312_New_Madrid_earthquakes
Felt way beyond the Northridge one.
http://latimesblogs.latimes.com/lanow/2012/02/sylmar-earthquake-anniversary-dam-almost-collapse.html
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