Earthquake devastation will be far worse
(This story has been updated to reflect the correct title of Sherilyn Lombos.)
The "Big One" will devastate the Portland area even more than scientists expected, according to a new state geologists' study of how a major earthquake will affect the tri-county area.
The study, released Thursday, March 15, found that a magnitude 9 earthquake centered off the Oregon Coast in the Cascadia Subduction Zone would cause tens of thousands of casualties in the Portland area, displace tens of thousands of residents from their homes, and cost tens of billions of dollars in building damage.
In Portland alone, the study calculates 119 to 896 immediate deaths from a major Cascadia earthquake, depending on when it occurs, plus hundreds to thousands more life-threatening injuries and people requiring hospitalization.
Throughout Multnomah County, 302 to 677 buildings can be expected to collapse.
"Although damage estimates vary widely throughout the study area, no community will be unharmed," the authors concluded.
Though considerably less likely, an earthquake of magnitude 6.8 epicentered in Portland's West Hills would be even more catastrophic locally — causing more than twice the casualties and damages — according to the Oregon Department of Geology and Mineral Industries study.
That would prove more devastating than a Cascadia earthquake for those living within 15 miles of the fault, scientists concluded.
In such a quake, as many as 120,000 Multnomah County residents could be displaced from their homes, or nearly one in six people.
Recovering from a Cascadia earthquake won't be just a matter of putting out fires and stemming floods. There will be region-wide challenges to restore power, bridges and freeways, provide emergency medical care and assure food and water can be delivered.
It will take months just to inspect homes and other damaged buildings to see if they're safe. Meanwhile, many will have to find other shelter, and some work places will have to be closed or relocated.
Mike Lueck, emergency management coordinator for the city of Tigard, was direct in his reaction to the latest report, pointing out that no one will ever really be ready for "The Big One."
"However, we are better than we were yesterday and we'll be better tomorrow," he said. "We have not seen the catastrophic impacts in (the Northwest) like we expect. We do have plans and checklists that are tested and updated annually with best proven practices."
Lueck said near-term improvements and preparations for a large quake include updating communications and working more closely with amateur or ham radio operators.
In addition, Tigard is improving citizen outreach, including offering free training on what to do in case of a disaster along with coordinating closely with all surrounding jurisdictions. That means periodically testing information technology platforms that would be needed to report damages, he said.
Meanwhile, Lueck said the city is aware of the new information released this week and is trying to update its earthquake plans as well as seismic maps, putting together an updated community outreach plan as well as improving its social media outreach.
At the same time, Tualatin is continuing its preparations as well with city officials highlighting the need for cooperation in any disaster.
"We know how important partnerships are in times of crisis, so in Tualatin we are focused on partnering with our fellow jurisdictions, neighborhoods and first responders to ensure we are coordinated in the event of a natural disaster," said Tualatin Mayor Lou Ogden. "Training, equipment, and technology are all vital components of our overall strategy."
Tualatin City Manager Sherilyn Lombos said the city continues to conduct regular emergency drills and each employee has a 72-hour disaster kit. A member of the Washington County Emergency Management Cooperative Executive Committee, Tualatin uses major weather events to practice emergency preparedness and also works closely with ham radio operators, she said.
In addition, the Community Emergency Response Team, also known as CERT, has 100 community members trained for disaster preparedness.
Lombos said residents in several neighborhoods have used the on-line Map Your Neighborhood tool to identify such important resources such as available generators along with noting where food supplies are located.
At the same time, Tualatin is constructing a new water reservoir designed to provide resiliency in case of a quake as well as assessing the emergency needs of the manufacturing businesses in the city using hazardous materials.
The city is also aware of the latest geological study.
"Tualatin has seen the study and will be using the information to help us better understand and prepare for the potential earthquake impacts," Lombos said.
New software, new findings
The new study, while showing more severe impacts than previous estimates, didn't bring any surprises or point to any new prevention efforts that haven't been considered before, said Dan Douthit, spokesman for the Portland Bureau of Emergency Management.
"We've already been expecting significant damages," Douthit said, "and every year that goes by, we get more and more prepared."
Emergency planners still will focus on the region's greatest vulnerabilities, including more than 1,600 unreinforced masonry buildings in the city of Portland. "We know that unreinforced masonry buildings are likely to collapse, especially during a Cascadia Subduction Zone earthquake," Douthit said. "Those pose an immediate life safety risk for people in them and people walking by during an earthquake."
But the new study, using more sophisticated Hazus software developed for the Federal Emergency Management Agency (FEMA), enabled scientists to drill down to damages at the neighborhood level as never before. The software is being constantly refined, incorporating real-world experiences from floods and earthquakes taking place around the world.
That enabled scientists to calculate the number of deaths, life-threatening injuries and hospitalizations that will occur in different neighborhood clusters in Portland and cities around the tri-county area.
Scientists now calculate there have been at least 40 large-magnitude earthquakes over the past 10,000 years along the 600-mile-long Cascadia Subduction Zone off the coasts of Oregon, Washington and Northern California. The most recent one occurred in 1700, and one recent study calculated there is a 15 percent to 20 percent chance that another one will occur in the next 50 years off the central and northern Oregon Coast.
The Portland Hills fault is directly beneath downtown Portland and extends into population centers of Clackamas County, and thus local damages could be much greater. However, there have been only two ruptures there in the last 15,000 years, according to the study.
Much of the damage from an earthquake depends on its severity and when it occurs. There will be fewer people injured if one occurs at night while people are sleeping, as wooden-frame homes are about the safest type of building construction during earthquakes. Quakes occurring during the daytime in the rainy season, when the soils are wet, will cause the greatest harm.
In the city of Portland, a major Cascadia quake could cause 675 deaths, life-threatening injuries and hospitalizations if it occurred during a late night during the summer. If the same quake occurred during the day in the rainy season, the number of serious casualties would jump to 4,549, according to the study.
Many minor casualties suffered during a quake could be addressed via simple first aid. The study points to the need for more people to get trained in first aid and how to respond to emergencies in their neighborhoods, Douthit said. Such training is provided for people volunteering with the city's Neighborhood Emergency Teams.
Those volunteers can take some of the load off hospitals, which are likely to get overwhelmed during a major quake.
As bad as conditions will be in the tri-county area under either scenario, it will be far worse on the Oregon Coast should there be a major Cascadia rupture.
"A tsunami danger from a Cascadia earthquake has the potential to kill more people than the ground shaking in Portland," Douthit said.
State geologists plan to release a second phase of their study next year, charting the potential impacts to Clark County, Washington and Columbia County, Oregon.
(Reporter Ray Pitz also contributed to this report.)