Seattle – You Have Significant Faults

I have just finished reading a chilling science book. Note I did not say science fiction. It is about earthquake, and it is about where we live, the Pacific Northwest.
full rip 9.0
The title is Full Rip 9.0 by Sandi Doughton the science reporter for The Seattle Times. The book describes a great awakening of earth scientists to the fact that this region periodically has a mega-quake, one that would register at 9 or greater on the Richter scale.

We have had lower registering quakes in 1949, 1965 and 2001. These are merely an overture. The fault of most concern which has been discovered off the Washington coast, the Cascadian Subduction, where the San Juan plate slams into North American plate. cascadian fault

Indian legends of earth shaking one winter night and the sea sending great waves to wash away the coastal people are true it turns out. Digging in the marshes out by Ocean Shores the scientists have found great bands of sand in between the mud of outflowing streams suggesting tsunami. Further, the tree rings in cedars killed at that point by flooding, the ground dropping and seawater rushing in, help date the last megaquake in these parts was set at 1700. Japanese records show a Tsunami washing up on their shores on January 26th that year, so this is the accepted date of the last Cascadian earthquake.

Ninety Two years later HMS Discovery sailed these waters and Captain Vancouver named the sound after a member of the crew, Puget, but he also had aboard a naturalist named Menzies who I believe noted the strange land form at Bambridge island, a bench that appeared to have been thrust up from the sea. Vancouver named it Restoration Point after the restoration of the Monarchy in Britain roughly 100 years before. HMS disovery on puget sound

Had they sailed east the naturalist would have found what we call Alki point. This is the same land form on the other side of the sound, and it follows what we now call the Seattle Fault.

There are many other faults shallowly running around where we live, including one called the Whidbey Fault that starts on the island and runs east under south Everett, through the Cascades and into eastern Washington. So ladies and gentlemen, we can say we all have our own faults.

These can and have caused trouble. But nothing like the quake of 1700. This time around we are not natives, camped on Hat Island or coastal Salish people caught in a Tsunami, without a means to record and report the disaster.

What will it look like? According to science, Doughton reports, a lot like the March 2011 quake which struck Japan, causing a level 7 meltdown of the Fukushima nuclear plant and a tsunami sweeping hundreds of people out to sea.seawall breached

The planning Japan does for earthquake is great, yet in this instance the evacuation planning didn’t adequately measure the size of the tsunami. For one port they had spent $1.6 million on a breakwater with gates to allow ships in to hold back the wave. The tsunami merely flicked this structure aside. Some who went to the evacuation points were overwhelmed by water anyway, those that kept running for high ground turned to see the evacuation building they were to go to being washed out to sea. Three years after this mega thrust there were still 2601 people missing.
japan-earthquake2
Burned in my memory is the picture of a young, well groomed and modernly dressed Japanese woman sitting among the rubble, weeping. And that ladies and gentlemen, will be us. The Japanese offshore fault looks like our offshore fault. japan

The predictions as to disaster are as follows; all the bridges in Western Washington, particularly those on Interstate 5, are likely to fall. Structures built before 1970 that have not been seismically retrofitted will collapse. Water, electricity, telephone and gas lines are likely to rupture. Several firehouses will collapse, some hospitals may too. We may not see any kind of rescue for weeks. The Space Needle will remain standing. apocolyptic seattle
When will this happen? We don’t know. It could be as you are reading this column, or well after your grandchildren are grandparents themselves. The best educated guess is the Cascadian subduction slips every 200 to 1000 years. We are at year 315 and counting.

Cascadian – it is our fault.


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