Don’t be alarmed Thursday morning when the coastal tsunami sirens blare out with the piercing wail of imminent danger rather than the standard soothing musical Westminster Chimes.

It’s all part of the Great Washington ShakeOut, the nation’s largest earthquake exercise, timed for 10:18 a.m. on Oct. 18.

For the first time, all of the coastal sirens in Washington state will be tested using the real sound of the siren, not the chimes that typically happen during the monthly tests. During previous ShakeOut drills, some jurisdictions had opted out, but all of the sirens will activate now.

Last year, more than 1 million Washington residents signed up to practice their earthquake readiness during the annual earthquake drill, which included participation from North Beach schools among local readiness efforts.

People and organizations can sign up to participate at www.shakeout.org/washington.

“Practicing drop, cover and hold on skills on a regular basis builds muscle memory so when an earthquake does hit, you’ll know instinctively what to do,” said Robert Ezelle, director of Washington Emergency Management Division. “We also want residents to take a look at your emergency kits. It’s important that you’re two weeks ready, not just for earthquakes, but big storms and power outages.”

Earthquake experts from Pacific Northwest Seismic Network, Washington Emergency Management Division, Washington Department of Natural Resources and FEMA Region X will be on hand for a Reddit Ask Me Anything – an online Q&A starting at 11 a.m., Oct. 11. The public is invited to ask questions at https://www.reddit.com/r/IAmA/.

A Facebook Live Q&A will also happen at about the same time at https://www.facebook.com/WashEMD/

Participants are encouraged to take photos of themselves participating in the drill and post those photos to social media using the hashtag #ShakeOut or tag our Twitter account at @waShakeOut.