PORTLAND — Unless Oregon gets better prepared, an inevitable magnitude 9.0 earthquake off its coast could kill thousands of residents and cause more than $30 billion in damage to the economy, a state earthquake commission says.
The findings are in a draft Oregon Resilience Plan that calls for the state to make 50 years of seismic upgrades and other improvements to limit the damage, the Oregonian reported Tuesday.
“Oregon faces a very real threat of permanent population loss and long-term economic decline,” said the commission created by the Legislature. It said the damage estimate represented a fifth of Oregon’s gross state product.
Awareness of the threat posed by a Cascadia subduction-zone earthquake has been growing in Oregon in recent decades — geologists say a big quake can be expected, but its timing can’t be predicted. The Legislature passed a resolution in 2011 calling for the report.
The commission ran a simulation of the impact in Oregon of a quake and tsunami like the one that struck Japan in 2011. The simulation found earthquake deaths ranging from 650 to 5,000, with another 600 to 5,000 deaths from a tsunami.
The report said severe shaking, probably for more than three minutes, and inundation would cause “near total damage” in a tsunami zone where 22,000 people live and 15,000 work.
In Western Oregon, it said, the damage would be vast, with utility and communications service knocked out, and transportation crippled by collapsed bridges. Aging tanks holding the state’s main fuel supply along the lower Willamette River would probably rupture as soil undergoes liquefaction, the report said.
Tens of thousands of buildings would be severely damaged, and restoring full utility service would take three months to a year in western valleys and far longer on the coast, the commission found.
Stan Watters, a Port of Portland manager who examined energy issues, was struck by the predicament of emergency workers who wouldn’t be able to drive because fuel stations would have no electricity to pump gas.
“Service stations should have to put in a secondary device” to pump gas, said Watters. “But even that is only a few days’ supply.”
The draft report upends decades of emergency preparedness doctrine, such as the idea that residents should prepare to be self-sufficient for 72 hours during a disaster.
“That makes me crazy. It’s not nearly enough,” said commission member Susan Steward, executive director of the Building Owners and Managers Association of Oregon. “It’s not like the Super Bowl, where everything’s going to magically come on in 34 minutes.”
A Cascadia earthquake is just as likely to occur today as 50 years from now, according to geologists. But commission members believe that fixes over half a century could make a difference.
The commission recommended that Oregon fully fund seismic upgrades for schools, hospitals and major highways, retrofit ports and airports and create a state Resilience Office.
“We cannot avoid the future earthquake,” the report said, “but we can choose either a future in which the earthquake results in grim damage and losses and a society diminished for a generation, or a future in which the earthquake is a manageable disaster without lasting impact.”