Are you ready for the 'Big One'?

When Harry Smedes talks about the Big One, there's no subjunctive mood. He doesn't say, "If it were to happen." He says, "When it happens."

The Big One is the magnitude-9.0 quake that will rock the Northwest and wreak havoc the likes of which the region has not seen since settlement by people of European descent.

"It's nine months pregnant," Smedes says of the Cascadia Subduction Zone.

He was speaking to a North Valley Community Watch crowd in Josephine County Tuesday night. A geologist and earthquake expert who has taught as an adjunct at Southern Oregon University, Smedes earned a Ph.D. in geology from the University of Washington and was a research geologist with the U.S. Geological Survey for many years.

"I expect to see it in my lifetime," he says of the Big One. "And I'm 86."

There is an iron-clad principle of journalism that if it hasn't rained for a record number of days, and you print that, it will rain within 24 hours. So it's with some trepidation that I mention the Big One, but here goes.

The subduction zone is about 50 miles off the Oregon and Washington coasts. That's where the Juan de Fuca plate is diving under the North America plate. It's doing it right now. Smedes demonstrates by having one hand bend the other hand down until it releases with a snap.

The plates are moving against each other at a rate of about one-and-a-half inches a year. As the ocean plate gets pushed deeper beneath the continental plate, it heats up. At some point it will lose the ability to store mechanical stress and trigger a monster quake.

This has been going on for about 200 million years. The process causes the volcanism that showed up at Mount St. Helens in 1980 and Mount Mazama, or Crater Lake, about 7,700 years ago.

The last Big One was at about 9 a.m. on Jan. 26, 1700. There have been seven in the past 3,500 years. They have followed each other by intervals of as long as 910 years, but they have also come at intervals of 210, 250 and 330 years. It's now been 313 years.

Think of the biggest quake you can imagine. Now multiply that by 1,000. A great quake is one with a magnitude of 9.0 or above on the Richter scale. The 1989 Loma Prieta quake in California was a 6.9.

But the scale, which measures the amplitude of the waves on seismographs, is logarithmic. A 9.0 quake has 10 times the amplitude of an 8.0 quake and 100 times that of a 7.0. Each 0.2 doubles the energy released. A 9.0 quake releases about 32 times the energy of an 8.0 and more than 1,000 times the energy of a 7.0.

Smedes speaks of large-scale devastation and loss of life. Electric, gas, water and sewer services will be disrupted, and many buildings, bridges and roads will collapse. And yes, he says, the Oregon Coast can look for a massive tsunami.

Maybe it's because he's a former Eagle Scout, and you can take a geologist out of the Boy Scouts, but you can't take the Boy Scout — and that Be Prepared motto — out of the geologist. But Smedes warms to the topic of disaster preparedness.

He recommends talking about preparedness with family members and neighbors. He suggests having a "buddy squad" to check on elderly or disabled neighbors.

"Disasters hit the very old and the very young the worst," he says.

And when you feel the Earth move beneath your feet?

"Don't try to get outside," he says. "You might not make it."

Avoid exterior walls, which may be hurling shards of glass. And, at the risk of sounding like those absurd civil-defense drills for schoolkids of the 1950s, duck and cover. Smedes says to hunker under or next to a desk or sofa or other large object that will take the brunt of collapsing materials.

You should have survival kits, he says. One for long-term, one for the car and a quick "grab and go." Store water and nonperishable food. And tools, plastic bags, batteries, blankets, clothes and sleeping bags. Candles, buckets, a camp stove, flashlights, knives, hand sanitizer and lotion, a mess kit and more (see for lists and suggestions).

And, of course, that one item without which civilization as we know it couldn't exist: duct tape.

Although he's speaking Tuesday night, it's as if Smedes anticipated the question that appeared in the MT's "Since You Asked" feature Friday morning: Barbara H. of Medford wondered where an earthquake kit might be stored "that might offer hope of finding it in the rubble if the house collapsed."

Good question. Geologist Eric Dittmer suggested a large tub placed on a patio or in a garage. Smedes doesn't like the garage.

"It might collapse, or you might not be able to get in it."

He suggests a small outdoor structure such as a garden shed.

Upping the ante on all this, the Oregon Department of Transportation this week released a plan that should cause eyes to open, if not jaws to drop. Faced with the impossibility of repairing Interstate 5 quickly due to its many bridges, ODOT announced it will instead work to get highways 97 and 58 reopened for use as the state's main north-south corridor. Stuff may not be able to get in or out.

You might want to think about being on your own for some time, folks.

Bill Varble is a freelance writer living in Medford. If you have comments or suggested topics for the column, please send them to

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