They say the quake off the coast of Japan ripped a hole in the sea floor 186 miles long and 93 miles wide. http://www.foxnews.com/us/2011/03/11/japan-quake-ranks-5th-largest-100/?intcmp=obnetwork
If that had happened on land? Wow. Hard to even grasp how big a rupture that is. Let's give it a try.
Anda and I looked at a map with a scale on it and started doing some measuring. We determined that a rupture 186 miles long would be from the Utah-Idaho border all the way down to about 10 miles south of Nephi. In other words, the entire "Wasatch Front" part of Utah where most of the population lives. Width-wise, think from the far side of the Great Salt Lake all the way across all the valleys where all the biggest Utah Cities are and across the Mountains almost to the border with Wyoming.
In other words, if a rupture like that happened in Utah, the Wasatch Front would be gone, along with 85% of Utah's population (http://en.wikipedia.org/wiki/Wasatch_Range). YIKES!