The Canadian Armed Forces are prepared to deploy thousands of members if a catastrophic earthquake, colloquially known as The Big One, strikes the West Coast.

The military plan for response to such an earthquake in B.C. is code-named Operation Panorama.

Royal Canadian Navy Capt. Steve Jorgensen, the Esquimalt, B.C.-based officer in charge of implementing the domestic disaster response plan, said after a disaster occurred all of the 5,000 to 6,000 regular and reserve military members in B.C. would be required to report to their units immediately, after ensuring their own family members' safety.

Jorgensen said the military would play a supporting role under direction from provincial emergency management officials.

A volunteer "victim" awaits medical attention during a disaster training exercise which simulated the aftermath of a catastrophic earthquake and tsunami in the Port Alberni area on Vancouver Island. (Government of B.C.)

"Local commanders are authorized without any further orders to do what they can in their immediate area to prevent loss of life and reduce suffering," he said.

Plans for assistance run from medical care and clearing debris to using ships and aircraft to deliver emergency supplies to remote or cut-off locations.

There have been no earthquake-related deaths in Canada in modern history, but scientific consensus is that will not forever be the case on the West Coast.

Military and civilian response to a disaster is coordinated through the Provincial Emergency Communications Centre, shown in a Port Alberni training exercise. (Government of B.C.)

A new study by structural engineers of potential earthquake damage to the city of Victoria, released last week, concluded that nearly 40 per cent of the city's buildings as well as much of the water and sewage infrastructure could be destroyed by a magnitude-9 megathrust earthquake centred off the west coast of Vancouver Island.

The likelihood of that scenario occurring in the next 50 years in Victoria is five per cent, according to the study's co-author, Armin Bebamzadeh.

Other B.C. municipalities, with the exception of the District of North Vancouver, have not commissioned similar assessments of earthquake damage risk.

However Vancouver is expected to suffer heavy damage and casualties along with Victoria in the event of a megathrust earthquake.

Volunteers act as disaster victims during the June 2016 Port Alberni earthquake and tsunami training exercise for military and civilian responders. (Government of B.C.)

Operation Panorama anticipates severe damages and a significant number of fatalities and injuries across Vancouver and Victoria, extending more than 100 kilometres from the epicentre of the quake.

The main cause of deaths would be the collapse of buildings and other manmade structures, the plan says. A significant percentage of hospitals and schools would be non-functional in the immediate aftermath.

We've planned for it, but there's a saying in the military that no plan survives first contact with the enemy - Royal Canadian Navy Captain Steve Jorgensen

The focus in the first days would be to save lives. After that restoring essential services becomes a priority.

"We've planned for it, but there's a saying in the military that no plan survives first contact with the enemy," Jorgensen said.

While municipal and provincial resources are expected to be quickly overwhelmed, the military will face its own challenges. For example, Jorgensen said, a tsunami could occur soon after the earthquake, but the navy's fleet of ships probably won't have time to get out to sea to avoid the surge.

Chris Duffy, the executive director of operations for Emergency Management BC, said the military's assistance will be crucial in the earthquake aftermath.

Military assistance not enough

"They have the infrastructure, equipment and training to come together and work in a chaotic environment, and that's the foundation," he said.

However, even bringing in the Canadian Armed Forces won't be enough to respond to the scale of the damage anticipated from The Big One, Duffy said.

"We'll need partners from around the world to come and assist." he said.

Jorgensen points to mutual aid arrangements with the United States, though the US West Coast is also at risk from the same Cascadia fault that extends from northern Vancouver Island to California.