PORTLAND, Ore. (KOIN) – Researchers at Oregon State University have developed a model for predicting how regional infrastructure will fare in a Cascadia Subduction Zone earthquake and how long it could take communities to recover.
The new research involved transportation networks, but the university said it can be used in other networks as well, such as water and electrical power networks. The study focused on 18 communities along the Oregon coast, from Astoria to Brookings.
“Our work looks at the connectivity of Oregon communities after ‘the really big one’ and how long it might take the transportation network to recover from the damages due to a magnitude 9 earthquake and tsunami,” said co-author Dan Cox, professor of civil and construction engineering at Oregon State.
He said researchers looked at connectivity from two perspectives: a local index related to getting around within a community, and a regional index related to going from the community to other locations.
The study showed that without regional considerations, recovery time may be severely underpredicted.
Cox said his team plans to take its results to the 18 Oregon communities it studied.
The researchers analyzed the communities individually and together as a regional network and considered factors such as earthquake ground shaking, tsunami inundation depth and proximity to airports and to highway and bridge maintenance facilities.
“In some instances, regional recovery happens faster than local recovery, such as North Bend and Coos Bay, whereas in other communities, such as Toledo, the local recovery is faster than the regional,” said College of Engineering doctoral student Dylan Sanderson.
For some communities, such as Rockaway Beach and Lincoln City, the regional and local recoveries are predicted to happen at about the same pace, he said.
“By comparing our results to other work in which the regional network was not considered, the time to recover for a single community was shown to be four times longer than previously estimated,” Sanderson said.
The communities the study predicted would recover fastest had access to roads that were identified as higher priority for restoration and also access to roads in areas with smaller hazard intensity measures. Communities that recovered quickly locally did so because of their access to maintenance facilities.
“We showed that adding additional maintenance facilities helped some communities, but others saw little to no improvement in local recovery time,” Sanderson said. “Communities that are more rural saw improvements in time to recover when an additional maintenance facility was added in the region, but communities closer to metropolitan areas experienced only minimal improvement.”
The study highlights some disparities in the recovery rate for coastal communities following large disasters. It shows that more work is needed to solve the issues.
Researchers hope this study can be used to support decision-making by different state or federal agencies.
The findings of the study were published in the Journal of Infrastructure Systems.