Getting prepared for what gets thrown at us

It has only been just in the last two or three decades that we who live in this beautiful part of the country have come gradually to learn that this is also the site of some of the greatest catastrophes the world has known. And some of them will repeat - perhaps in our lifetime.

We all know about the volcanoes, thanks to the eruption thirty years ago of Mt. St. Helens. But that was a small event compared to some in the past: Mt. Mazama blew itself to pieces in historic times, leaving behind the chasm that eventually filled with water, and is now known as Crater Lake. And both Mt. Hood and Mt. Rainier are volcanoes, considered active, and have erupted in the fairly recent past. Some now say Mt. Rainier is due for another big one.

The reason for our chain of volcanoes is the subduction of the undersea crustal plates of the earth off the west coast; our eruptive mountains form a dotted line defining where the oceanic Juan de Fuca plate is plunging beneath the continental plate we live on.

That subduction begins when the two plates encounter each other, and the oceanic plate grinds beneath the margin of the continental plate. That's happening under the Pacific Ocean, over a hundred miles off the Oregon shore.

We now know that this sort of constant grinding collision, happening in exquisite slow motion, is what causes the world's largest earthquakes every now and then. The last one here happened on January 26, 1700, at 9 o'clock in the evening, and is still recounted in Indian legends.

These huge earthquakes here have happened at intervals as far back as geologists are now able to peer; and the average interval between them is less than three hundred years. It has now been three hundred eleven years since that last one, and geologists say we're due.

The geologists go on to describe what a Force 8-to-9 earthquake would mean here. Most obviously, there will be a huge tsunami along the coast, destroying the coast highway and most of the communities on the coast. Those not able to get to a sufficiently high place above the ocean within a half hour or less will be consumed by a massive wall of water.

The Oregon coast will not be a fun place to be for a very long time after that. In 1700, the coastline dropped three feet as the tension along the plate boundary released, drowning coastal forests - the remains of which are visible today. A similar release of tension will drop the coastline in a similar manner again.

The tsunami will not make it to Portland, if only because of the way the Columbia River bends at Longview. It will probably make it to Longview, they say. But Portland and inland western Oregon faces massive catastrophe anyway.

Five endless minutes of shaking will bring down brick buildings, cause the many ancient landslides around the area to get moving - one of them is under the west end of the Sellwood Bridge - break up the roads, dislocate houses from their foundations, bring down and smash endless furnishings and possessions, trap and injure many residents, killing some - and probably render all the bridges across the Willamette River unsafe or uncrossable.

Geologists say that Interstate Five will be so damaged that it may be months before it can open as a highway into and out of the area again, and Oregon will be cut off from Washington at the Columbia River. People will feel our earthquake at least as far away as Salt Lake City, and it could trigger an earthquake on the San Andreas fault in California.

Since all the infrastructure here - electricity, water lines, phone lines, cable lines, gas pipes, wireless communications - will be broken, it may be some time before local families divided by the river are even able to find out if those who crossed a bridge that day are all right.

If it happens in January again, we'll all be camping out in the yard in the rain for quite some time. Those injured may have to wait a while for medical treatment; neighbors will rely on neighbors. Food and water will be in short supply for an extended period.

So, do we all just give up any hope of surviving this inevitable event - or shrug and simply hope it happens after we're gone, and go about our business?

There are steps that can be taken. Creating a secure stockpile of potable water and canned foods (along with a can opener) would be a start. Cacheing some blankets and maybe a tent would be another. Joining your neighborhood NET team would be a very good idea.

These Neighborhood Emergency Teams are formed in most neighborhoods, and receive fire department training - but they have had difficulty attracting local residents to join them, because so few neighbors have taken this situation seriously.

The NET teams work to come up with plans for addressing a catastrophe - where to go, what equipment to stockpile, what techniques to use when rescue is entirely up to neighbors - and form local networks. They work with Ham radio operators to make plans for the only emergency communications there will be.

Need any more incentive to take precautions and make plans for the inevitable disaster, if it takes place while you are living here?

Well, then, consider this: The reason we know exactly when the last Force 9 earthquake did happen here is that it spawned a tsunami that rolled ashore in Japan and caused much destruction and loss of life. The Japanese, used to earthquakes, since they live near the same crustal boundary that we do, recorded with surprise the 'orphan tsunami' that arrived without a preceding earthquake.

Yes, the Japanese are used to big earthquakes of this type. They thought they were ready for anything - but the recent earthquake in northern Japan shows that even their elaborate precautions were not enough to withstand a Force 9 subduction earthquake.

And the Japanese are FAR more prepared than we are. We still have unreinforced brick buildings downtown and in all the neighborhoods that will shake apart and fall in ruin when the Big One hits; we didn't even know we were vulnerable to such earthquakes until geologists turned up the evidence within the last half century.

Since we WILL have an earthquake of this magnitude one of these days, best to start making some basic preparations now.

And seriously - contact your neighborhood association about joining your local NET team. The more people on it, the better off we ALL will be…when disaster strikes.

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