BEND, OR -- Central Oregonians are encouraged to prepare for “The Big One” by participating in Thursday's Great Oregon Shakeout. The annual event takes place nationwide on 10/20 at 10:20 a.m. local time.

Althea Rizzo, with Oregon's Office of Emergency Management, says we should ask ourselves how we would respond if the earth started quaking, "What would I do right now if I needed to drop, cover and hold?"

The biggest threat is from the Cascadia Subduction Zone running along Oregon's coast. Rizzo says concerns about a large-scale quake are not "if" but "when." She tells KBND News, "It will happen at some point; we will have a major earthquake that will severely damage our infrastructure, our transportation systems, our economy, our healthcare systems, and then, over on the coast, we know we’re going to have a very large tsunami."

When The Big One does hit, Rizzo says the response is simple and immediate, "Drop, cover and hold on until the ground stops shaking. And then move to a safe place outside of the building until you know that the building is safe. If you’re over on the coast, once the shaking stops and you leave the building, then we want you to get to high ground as soon as possible - not waiting for anyone to tell you to get to high ground. Just know that the shaking is your tsunami warning."

It’s been a few hundred years since the last Cascadia Subduction Zone quake and, she admits, no one knows when the next one will happen. Instead of getting complacent, she encourages everyone to use the Shakeout to plan ahead for any disaster or emergency, "The opportunity, starting with the Shakeout, to kind of look at your whole household preparedness as we head into winter. Cascadia may be 200 years, but we have other things that we can prepare for in the meantime."

Learn more and register as a participant at shakeout.org/Oregon.  More than half a million Oregonians have already signed up to take part. You can also download the “MyShake” app and get a test alert at 10:20 a.m. on 10/20.