Tuesday, October 29, 2013

Geo 365: Oct. 29, Day 302: Basalt Terrace

A mile or so north of Otter Rock, there is a shelf of elevated terrace developed on the Columbia River Basalt flows. This creates a nice flat space that can be developed for residences or vacation homes. I'm guesstimating these are about 60-70 feet above sea level, so they're probably out of the tsunami risk zone in the event of a great Cascadia quake/tsunami. And since you ask, no, I can't go to the coast these days without posing questions like that to myself. It's not a phobia, it's not even really a "jittery" feeling. It's more than simply an intellectual curiosity, though. I consider it a sensible feeling of caution, like consciously scanning a street scene before I cross... "Is it safe?" In addition, having the foundations of these dwellings directly on bedrock means that the effects of the shaking will probably be less severe than if they were on unconsolidated fill. Long and short, this is a highly desirable spot for development, and not just for the view.

Photo unmodified. May 6, 2013. FlashEarth location.


Dan McShane said...

I have a similar reaction, and where I see development at risk I have a feeling of dread

Lockwood said...

Some of the buildings on the coast that have been put in over the last 20 years- SINCE the hazard was well-known- are just insane. Here's one that's been in place since the 70's that makes me shiver, an the development that's gone on at Bandon is insane. http://outsidetheinterzone.blogspot.com/2013/02/geo-365-feb-4-day-35-alsea-spit.html