County and state emergency management organizations offered practical tips to prepare for tsunamis at the second annual Tsunami Roadshow, which took place at Chimacum High School April 13.

When asked by an attendee about when residents of the region might expect the next tsunami, Carrie Garrison-Laney, tsunami and coastal resilience liaison for the University of Washington, explained that previous data had indicated tsunamis occur roughly every 500-600 years. However, she noted, evidence of a tsunami in the sediments of Discovery Bay suggest those events could occur more closely together.

Because of the water that flowed into and was trapped in Discovery Bay, Garrison-Laney elaborated, scientists have determined the exact date of the most recent tsunami to have been Jan. 26, 1700. Moreover, because of the friction between tectonic plates, they do not move past each other at a steady rate, instead remaining largely locked for extended periods of time, before giving way to sudden shifts.

“So we can’t be complacent,” Garrison-Laney said.

Daniel Eungard, a geologist for the Washington Geological Survey, quantified the tectonic plate uplift as 1-3 millimeters per year, measurements that geologists have begun recording with same sort of global positioning systems that motorists use for directions while driving.

While a “large” release of energy from the plates is estimated to occur every 2,500 years, Eungard warned that even a “small” event could yield an earthquake measuring 8.7 or 8.8 on the Richter scale.

“In the worst-case scenario, you’d have 12-foot-tall waves that would reach all the way to the bluffs,” Eungard said. “The downtown and harbor would be hit pretty hard.”

Eungard advised residents to be aware of the fastest routes to higher ground from where they are.

Keily Yemm, tsunami program coordinator for the Washington State Military Department’s Emergency Management Division, explained that the national tsunami warning centers in Alaska and Hawaii use a network of deep-ocean tsunami detection buoys and satellites to measure not only seismic waves moving through the sea floor, but also the change in height between the sea floor and the water above.

To be alerted in the event of a tsunami, residents can sign up for text alerts through Jefferson County at jeffcoeoc.com and the Washington State Department of Transportation at wsdot.wa.gov. Area radio stations KPTZ-FM 91.9 and KROH-FM 91.1 also partner with the county Department of Emergency Management in the event of an earthquake or tsunami. You can also buy a National Oceanic and Atmospheric Administration weather radio at electronics stores.

Maximilian Dixon, earthquake program manager for the Washington State Military Department’s Emergency Management Division, urged residents not only to know their evacuation routes, but also to have emergency plans worked out for their homes and workplaces, and a “go bag” of supplies ready to take with them.

“How will you communicate with friends and family?” Dixon asked. “How can you involve your neighbors in community-wide preparations?”

Warning signs of an impending tsunami include the ground shaking for up to 5 minutes and a rapid fall of sea levels. Dixon discouraged evacuees from getting into their cars, not only because they and other drivers are likely to be panicked and prone to accidents, but also because of the danger of falling trees and power lines.

“You should plan to be on your own for a while in the aftermath,” Dixon said. “Help will be slow in coming. Coastal areas are especially prone to isolation, so prepare to depend on yourselves. Stock up for 30 days. Have warm clothes. Keep as dry as you can. Have water purification methods. And include some comfort items to lift your spirits. For me, that’s chocolate.”

Dixon gave attendees a “homework” assignment that night, of stocking a sturdy set of old shoes, a flashlight, a jacket and their glasses all within immediate reach of their beds, so they can go at a moment’s notice.

“The no. 1 injury at night after an earthquake is cut feet,” Dixon said.