SHELTON, Wash. (AP) -- The parachutes slowly float down from Chinook helicopters, first carrying boxes of supplies and then the paratroopers who set up a field operations center as part of a readiness drill for a megaquake and tsunami.
Chief Warrant Officer James Pierce packed up his parachute and grabbed his gear shortly after hitting the ground Thursday at Sanderson Field, an airfield in the small city of Shelton on the west side of Puget Sound.
Parachuting in may be the only option for some responders following a massive earthquake, especially to get to remote locations that are rendered undriveable.
"It's a good, effective way to get gear to the ground," Pierce said.
Thursday's exercise was part of a four-day event that ends Friday, called Cascadia Rising, built around the premise of a 9.0 magnitude earthquake 95 miles off the coast of Oregon that results in a tsunami. Both events would likely destroy buildings, roads and buildings and disrupt communications.
For the drill, the airfield and adjoining Mason County Fairgrounds have been converted into a staging area with hundreds of members of the National Guard, a tactical operations center where officials communicate directly with officials at Camp Murray and a trauma center.
Emergency officials believe Shelton will be the closest airfield to the Washington coast -- about 70 miles west of Seattle -- to survive the disaster.
"After a Cascadia Subduction Zone earthquake, we fully anticipate that roads are going to be cut off, bridges are going to be down and we're going to have isolated pockets of people that are going to need some help and support," said Major General Bret Daugherty, commander of the Washington National Guard.
Research suggests that the Cascadia Subduction Zone -- a 600-mile-long fault just off the coast that runs from Northern California to British Columbia -- on average produces magnitude 9.0 quakes every 500 years. Big quakes have been separated by as few as 200 years and as many as 1,000, so it's impossible to predict when the next monster quake occurs. However, tectonic stresses have been accumulating for more than 300 years and seismologists say it could rupture any time.
Officials say about 20,000 people have been involved in the disaster drill throughout the Pacific Northwest, representing federal agencies, the U.S. military, and state and local emergency response managers from Washington, Oregon and Idaho, Native American tribes and emergency management officials in British Columbia. More than 8 million people live in the zone, which includes the population centers of Portland and Seattle.
One main goal is to test how well they will work together to minimize loss of life and damages when a mega-quake unleashes a tsunami. They're also testing their ability to communicate without the internet or phones; delivering services in emergency conditions; and search and rescue, decontamination and evacuation abilities.
On Wednesday, one exercise showed the Navy's capability to deliver personnel and equipment to a disaster zone where ports would be destroyed by tsunami waves.
The Navy sent the USNS Bob Hope with about 500 sailors to build a temporary camp on a Naval Magazine Indian Island, a munitions depot in the Puget Sound.
It took the Navy four weeks from loading the Bob Hope to setting up the camp -- a similar timeline would be expected after the earthquake.
In Port Angeles, a shoreline city on Washington's Olympic Peninsula, members of the Washington National Guard practiced decontaminating vehicles and first responders. Tsunami waves hitting this area would pick up biohazards while surging through land.
First Sgt. Kent Keller of the Washington National Guard said that these drills allow them to make mistakes now, so they don't make them later during the real thing.
"We are going to learn, and we're going to change the way we behave based on the lessons learned in this training," he said.
AP reporter Manuel Valdes contributed from Naval Magazine Indian Island.