With images of mayhem fresh in our minds from the Japanese earthquake, local experts emphasize that we can be sure of three things: A very big quake is coming to Southern Oregon, you can prepare for and minimize its impact, and you can buy earthquake insurance for a reasonable price.

With images of mayhem fresh in our minds from the Japanese earthquake, local experts emphasize that we can be sure of three things: A very big quake is coming to Southern Oregon, you can prepare for and minimize its impact, and you can buy earthquake insurance for a reasonable price.

At a Southern Oregon University seminar Friday, local disaster experts will show the inevitability of "the Big One," a quake of magnitude 8 to 9-plus that shakes this region every 300 to 350 years (it's been 311 years since the last one). They'll give tips on preparing survival kits and strategies for riding out the quakes in your house — and what to do afterward.

"Absolutely, it's going to happen here," said Eric Dittmer, SOU environmental studies teacher. "We're on top of a subduction zone and have a plate from the ocean going under our continental plate and melting, becoming the lava for Cascade volcanoes. There's the possibility it's going to happen under us because it's a broad zone."

The last "big one" in the Northwest occurred in the Oregon and Washington coastal ranges on Jan. 26, 1700, as determined by a tsunami recorded in Japan, Dittmer said.

It inspired the search for drowned trees and landslides of earlier big quakes, enabling scientists to calculate the average three-century interval.

If the quake happens on the edge of the San Juan de Fuca plate, 100 miles off the Oregon Coast, the Rogue Valley still would suffer quakes in the magnitude 6 range, he said, with tsunamis on the coast.

The only impact from water that might strike here during a quake would be damage to Hostler Dam, which holds Ashland's water supply, Dittmer said. The city conducts a monthly drill in which it sounds a citywide siren.

Retired U.S. Geological Survey geologist Harry Smedes of Grants Pass said the Cascadia Subduction Zone off Oregon is "nine months' pregnant and ready to go ... in a mirror image of what happened in Japan."

New research shows that the part of the plate off Southern Oregon delivers a major blow in a cycle as short as every 240 years, Smedes said. As in Japan, the oceanic plate steadily slides under and deforms the continental plate, but the continental plate must and will spring back violently, advancing 20 to 30 feet, he said.

As a yardstick of the region's seismic restlessness, the U.S. Geologic Survey, at earthquake.usgs.gov, notes that a 4.3-magnitude quake happened Tuesday, 100 miles offshore from Brookings — and another quake, of 2.1 magnitude, came April 12, nine miles east of Ashland.

Experts recommend residents keep a survival kit that includes a three-day supply of non-perishable food, mess kit, can opener, flashlight, batteries, solar battery charger, battery-powered radio, toilet paper, soap, toothpaste, local maps, cellphone charger, wrench to turn off utilities, plastic sheeting and duct tape to make a shelter in place, and water — enough for a gallon a day per person, according to the Federal Emergency Management Agency (see www.ready.gov/america/getakit/index.html).

"What you prepare depends on if you're leaving your house or not," said Heather Freiheit, SOU emergency management director. Residents also should plan for what to do with their pets, since they're not allowed in shelters. Families of infants should remember to pack diapers, wipes and baby food, she said.

Area residents are at a disadvantage in preparedness, Freiheit said, because disasters don't happen here that often.

"It's a challenge to get people ready," she said. "But, yes, we're going to have the big earthquake, probably in the next 50 years."

It's natural when you feel the ground shaking to want to run outside, but statistics show that more people get injured or killed by falling debris on their way to the door than get hurt by crawling under tables and desks, she said.

"All you have to do is look at the video from Japan and see that people couldn't stand, let alone run, so get in the habit of thinking what you can hide under," Freiheit said. "If there's no table, crouch and cover your neck next to an interior wall."

Don't seek cover by exterior walls with windows, which break into hurtful shards, she said. As for falling picture frames, you can minimize their harm by hanging them with actual picture hangers, not nails, and attaching them to studs inside walls.

You might think the stick-built frame houses of the Northwest won't offer protection against quakes, but the opposite is true, Freiheit said. Wood is flexible and can sway and absorb shock, while rigid masonry buildings tend to collapse.

"Quake preparation is a lot like baby-proofing your house," she said. "Attach dressers to walls, store chemicals in a locked cabinet, get everything secure as you can."

"Duck, hold and cover," Smedes said. "If in bed, roll onto the floor and pull pillows on top of you. Conduct drills, so you know what to do and don't run around in a panic. Closets or bathrooms are good because you have four walls close around you."

Earthquake insurance is available in the range of $300 to $500 a year, depending on the value and age of your house, and comes with deductibles of 10 percent to 25 percent, said Mike Neilitz of Allstate Insurance in Medford.

"I'd say about 5 percent of homeowners get earthquake insurance," said Neilitz. "It's most likely people from California, who have been through an earthquake."

John Darling is a freelance writer living in Ashland. E-mail him at jdarling@jeffnet.org.