Report: Earthquake could kill, injure 27K

News
earthquake analysis b 03152018 dogami_1521141684766.jpg.jpg

PORTLAND, Ore. (KOIN) – It’s a staggering statistic. 

Thousands of people are expected to be killed or somehow injured when a major earthquake hits, according to a newly released report. Depending on when a 9.0 Cascadia Subduction Zone (CSZ) earthquake hits, the death toll and number of injured could reach into the “low tens of thousands.”

The newly released report was prepared for the Regional Disaster Preparedness Organization (RDPO).

The report provides damage and casualty estimates to buildings, people, and key infrastructure sectors resulting from a major earthquake in the Portland metropolitan region by using updated local geologic information and recent advances in loss estimation methods.

Ali Ryan Hansen, ‎communications director for ‎Oregon Department of Geology and Mineral Industries, said the last ODGMI study was done in 1998. Since then, there have been significant advances in technology in areas of liquefaction and landslides associated to earthquakes. Researchers also have more data on building and population statistics and have been able to create more detailed maps when it comes to potential shaking and damage estimates. 

“We’re now light years ahead of where we used to be,” Hansen said. “What this study really shows is that we need to continue to work on reducing impact zones.” The report ran two earthquake scenarios: a magnitude 9.0 CSZ earthquake and a magnitude 6.8 Portland Hills fault earthquake — a local crustal fault situated at the foot of the Tualatin Mountains.

The report also provided a new potential shaking map, which shows the most violent shaking occurring in the hills of Washington County and along the Willamette and Columbia rivers in Multnomah County.

Most of the “casualties” from an earthquake are expected to be the walking wounded, according to Hansen. FEMA uses the word casualty to include those injured and those who die in a natural disaster. 

The worst possible outcome, according to the new report, shows that 27,000 people could be killed or somehow injured during a 9.0 CSZ earthquake that happens during the daylight hours. 

“These numbers do not have to be our reality,” Hansen said. 

The effects of an earthquake will vary depending on when the earthquake hits. 

Experts use two earthquakes that happened in New Zealand. One struck at 4:35 a.m. on Sept. 4, 2010 and the other 12:51 p.m. on Feb. 22, 2011. According to the report, no deaths occurred from the early morning earthquake, whereas the afternoon earthquake resulted in the deaths of 185 people.

A magnitude 9.0 earthquake along CSZ will have a severe impact on the tri-county area, with building repair costs amounting to between $23.5 and $36.7 billion, the report found. 

“Although damage estimates vary widely throughout the study area, no community will be unharmed,” the report states. 

The earthquake will generate several millions of tons of debris from damaged buildings. 

A graphic provided by the  Oregon Department of Geology and Mineral Industries from a report and analysis of how a major earthquake would affect the Portland metro and the state of Oregon, March 15, 2018

“Damage and casualty estimates resulting from a magnitude 6.8 Portland Hills fault earthquake are more than twice compared to a CSZ earthquake, primarily because of the Portland Hills fault location below densely populated and heavily developed areas,” the report finds.  

“However, the likelihood of a Portland Hills fault earthquake is considerably less than a Cascadia Subduction Zone earthquake.”

Damage estimates in the latest report are significantly higher than those given in previously published studies. The increase comes after researchers used updated building inventory “that more accurately reflects the region’s building code history with respect to seismic resiliency, and usage of updated soils and liquefaction susceptibility data.”

Hundreds of thousands of buildings in the study area will need safety inspections after a major earthquake. The report stressed that timely inspection of damaged buildings will reduce pressure on temporary shelters.

“The majority of buildings in the study area do not meet current seismic building code standards, although the buildings did meet code standards in place at time of construction,” the report states.

The authors of the report urge state and local government to offer incentives “and other options that encourage building owners to seismically upgrade their buildings.”

“Such upgrades will reduce casualties and building repair costs and will minimize potential loss of businesses and workforce housing. Jurisdictions can consider triggers that require seismic upgrades, such as a major building renovation.”

Post-earthquake emergency operations, the report states, can be enhanced by having an awareness of the types of population shifts between buildings throughout the day and week, and the seismic resiliency of those buildings.

The RDPO is a bi-state partnership of local and regional government agencies, non-governmental organizations and private-sector stakeholders representing the Portland metropolitan region that collaborate to increase the region’s resiliency to disasters.

Experts stress people should start preparing now for an earthquake. It’s advised people have two weeks’ worth of food and water. 

“The emphasis right now is on preparing,” Hansen said. 

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Twitter News Widget

Trending Stories