Thursday evening we went to a lecture by a geologist that discussed what and how the next great earthquake in the pacific northwest will be. Coincidentally, the lecture was on the 312th anniversary of the last great earthquake in the northwest which was on the par of what Japan experienced last spring. The reason they know the exact date of that earthquake is that there are still standing tree remnants in places that were carbon dated to have last been alive about 300 years ago. When looking at ancient records in Japan there was mention of a tsunami on Jan 26th, 1700, that did not have an accompanying earthquake (an orphan tsunami). They have deduced that the quake occurred in the northwest and it was about a Richter scale 9. The geological record shows that these quakes occur about every 300 to 500 years. What is alarming is that currently two plates are moving toward each other, one sliding under the other and they are currently stuck. The coastal mountains are rising about 3 inches per year because of the pressure. At some point the pressure releases and there is massive upheaval up to 600 miles in length. There is also risk of active volcanic activity.
Really scary stuff and it sure made us aware of watching for the tsunami warning signs that are posted along the Oregon Coast. Unfortunately, where we camped on Friday night was a long ways away from any high ground.