When it comes to earthquakes along Washington's Cascadia Subduction Zone, geologists say "The Big One" is coming - it's just a matter of when. That's why the state is already planning for its next large-scale exercise to prepare for when it hits.

This week, the Washington Emergency Management Division started initial planning for its second "Cascadia Rising," the region's largest disaster-scenario exercise testing how local, state and federal agencies would respond if a 9.0 magnitude earthquake hit along the Washington and Oregon coast.

The first Cascadia Rising exercise was held two years ago this month; the second will happen four years from now.

“The 2022 exercise will test the response of all four northwestern states (WA, AK, OR, ID) as well as British Columbia, FEMA, Public Safety Canada and U.S. Northern Command,” said Lit Dudley, the Exercise & Training Section Manager at the state Emergency Management Division.

Dudley said the new exercise will hope to incorporate new findings and steps recommended by the Resilient Washington Subcabinet, created by Gov. Jay Inslee after the first Cascadia Rising.

Other exercises between now and 2022 will also explore different kinds of responses. For example, in August, at the state and federal level, the state will conduct an exercise in the event of a widespread, grid blackout.

Watch: Where would 'The Big One' start?

“We are planning several ramp-up workshops in preparation for a 2022 Cascadia Rising,” Dudley said. “Workshops will focus on geological hazards, their science and how to prepare communities to respond. Other workshops will focus on planning for public safety, such as mass care and medical surge and for catastrophic damage to and restoration of major infrastructure, including communications, transportation and energy.”

Two years ago this June, the Washington Military Department - which includes the National Guard and the state Emergency Management division - executed the first "Cascadia Rising." During the four-day exercise, the National Guard prepared for 1,274,327 people needing mass feeding and water, 507,701 damaged homes and residential buildings, and 410,127 people needing emergency shelter. It even accounted for 254,357 pets requiring shelter.

Related stories:

How pressure is building for Cascadia earthquake

Cascadia Rising drill offers sobering assessment of future disaster response

Cascadia Rising 2016 After Action Report

Read more coverage KING 5's Disaster Preparedness section