Sunday, January 27, 2013

Visualize 313 Years Ago

Its a cold wet day in Bellingham - 30s and rain. A good time to hunker down and stay dry and warm. Its a bit milder out on the outer coast of Washington State, but the winter nights are long and it is still wet and chilly. I picture the residences of a small village at the Copalis River on the outer coast 313 years ago in their long houses and homes staying warm by the fire, telling stories, working on food, singing, maybe carving a box or weaving baskets and hats. Then the earth began to shake like it had never before done. Perhaps some rushed outside if they could stay on their feet as the shaking was so violent. Perhaps a long house collapsed from the bouncing earth. Terror in the dark.

When the shaking ended those unhurt would struggle trying to help the injured. There would be much shouting and confusion. About 10 to 15 minutes after the shaking, a new sound approached from the west. A roar as waves that could not be seen in the night began over topping the dunes between the village and the ocean. The waves smashed through the village snuffing out whatever fires were burning. Perhaps a few that lived near the slope above the river managed to get to high ground.

Sitka spruce stump at Copalis with tsunami deposit.

It is hard to visualize, but it was certainly a terrible night and likely survival after the event was very difficult. At other locations, entire communities would have been destroyed with few if any survivors.

This event will be repeated, with different homes and hopefully a bit more understanding on what to do. For geologists there is no debate on the if. There is uncertainty as to when, and given recent large coastal subduction quakes, the size may be larger than previously thought as well as the proximity of the quake to populated areas including the larger more inland cities.

For policy makers difficult choices. Investing in emergency planning, equipment and supplies for an event that may not happen in our lifetime. Planning emergency escape routes from tsunami waves, building escape towers when no reasonable escape routes are available. For development planning implementing new uniform building codes for really big earth quakes. Development restrictions at sites extra susceptible from earth shaking. Rules governing development in tsunami inundation areas.  

No comments: