Friday, October 21, 2016

Plate Tectonic Evolution of North America - Scotese Animation

Plate Tectonic Evolution of North America - Scotese Animation
(MA or Ma (mega-annum) is a million years) (4:59 minute YouTube Video)

Published on Dec 14, 2015
by Christopher Scotese The PALEOMAP Project Channel by Christopher Scotese has more than 50 computer animations showing the plate tectonic evolution of the continents and ocean basins during the last billion years.

This animation shows the plate tectonic and paleogeographic evolution of North America from 200 million years ago to the present-day. North America was originally part of thee supercontinent of Pangea. About 200 million years ago, Pangea rifted apart. To the east of North America, the Central Atlantic Ridge [Mid-Atlantic Ridge (MAR)]
The Mid-Atlantic Ridge (MAR) is a mid-ocean ridge, a divergent tectonic plate or constructive plate boundary located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. In the North Atlantic, it separates the Eurasian and North American Plates, whereas in the South Atlantic it separates the African and South American Plates. The Ridge extends from a junction with the Gakkel Ridge (Mid-Arctic Ridge) northeast of Greenland southward to the Bouvet Triple Junction in the South Atlantic. Although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level. The section of the ridge that includes the island of Iceland is also known as the Reykjanes Ridge. The ridge has an average spreading rate of about 2.5 cm per year.[1]
With the formation of North America, the North American Tectonic Plate is now colliding with the Pacific Tectonic Plate – and it's leading edge plates. The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres (40,000,000 sq mi), it is the largest tectonic plate, The north-eastern side is a divergent boundary with the Explorer Plate, the Juan de Fuca Plate and the Gorda Plate forming respectively the Explorer Ridge, the Juan de Fuca Ridge and the Gorda Ridge. In the middle of the eastern side is a transform boundary with the North American Plate along the San Andreas Fault, and a boundary with the Cocos Plate. The south-eastern side is a divergent boundary with the Nazca Plate forming the East Pacific Rise ....
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Seismic Hazard Maps for the National Building Code of Canada – past ...
Jan 13, 2012 - Geological Survey of Canada,. Natural Resources Canada, Ottawa, ... Size described by magnitude (one magnitude per earthquake!) Effects described by ... Magnitude-recurrence statistics near Toronto ... Probabilistic treatment of Cascadia. • Integrated .... Seismic hazard estimates are improving. More data ...\
Cascadia Magnitude-recurrence for complete rupture events ~ Synopsis
J Adams 20120113
[ever wonder why eggheads* use big words, just so the rest of us don't understand? Used here, prototypical is used to indicate that someone or something is a very typical.
(Over the last 10,000 years ~
10,000 year history (we have one sample of the 1/10,000 year event!). Assume that each rupture of interest to Canada is a complete, end-to-end (IE. all M~9**, not some M9 + many M~8) Use time interval * plate tectonic rate to get the slip per event
magnitude Protypical event happens every 550 years, ruptures length of 1020 km and width of 125 km, has slip of 25 m and has magnitude of 9.3
Events range in magnitude from 8.5 - 9.1 or 8.9 - 9.5 depending on input assumptions but nearby seismic hazard is not very sensitive to exact magnitudes when earthquakes get this big

Boy, you can say that again!***  - Stan G, Webb

*egg·head ˈeɡˌhed/ noun
informal derogatory
plural noun: eggheads
  1. a person who is highly academic or studious; an intellectual.
intellectual, thinker, academic, scholar, sage;
bookworm, highbrow;
expert, genius, mastermind;
** Here I believe the author is using the tilde ~ as a symbol for approximation. As we all learned in grammar school arithmetic, the formal approximation symbol looks like two tildes on top of one another (≈). I suppose the author could just have written, I don't know, but around M9, or M9±.
*** Following years of academia and study, when I was in practice, I would try to propose different options and plans and discuss those with my clients. After spending hours explaining several complex options, some would say “they just still did not understand; but, since I was so compelling, indeed, passionate in my beliefs, they told me to go head with the plan I had outlined”. They know that I always had their best interests in my heart and mind. Now, I said to myself, that is not how I want to practice. So I went back to night school to learn how to communicate, loosing all of that professional jargon. It took me 2 years, post-graduate. My clients all complemented me on my efforts. For the first time I made things clearer and easier for them to understand. Later was widely engaged as a keynote speaker and published author. Albeit some were tough, dark years.