Contrary to what many local residents believe, Eugene and Springfield are at risk for devastating earthquakes. The specific areas with the most risk for damage have been determined by state geologists who recently released an earthquake hazard map and an accompanying damage report for the area.
These reports change the long-held belief that Oregon cities had little to fear from earthquakes, said Bill Clingman, a geologist for the Lane Council of Governments, who also served on the advisory committee that helped put the map together.
“We need to be aware that this is a seismically active area,” he said. “We tend to think earthquake risk isn’t a factor, but it is.”
A previous study compiled by the Oregon Department of Geology and Mineral Industries that predicted the damage and economic loss in the event of a major earthquake listed Lane County as one of the most threatened areas in the state.
If an earthquake with a magnitude of eight on the Richter scale were to strike, Lane County would suffer $1.6 billion in economic losses and experience heavy damage to its structures, roads and essential services.
Clingman said the new map can be used to prioritize seismic retrofitting, plan the city’s future growth and determine where not to locate vital services. Though Clingman stressed that earthquakes are a threat, he did not want people to panic.
“It is not something I expect people to be awake at night worrying about, but it should be a concern,” he said.

Historical buildings

at risk on campus
The University and downtown Eugene are both in low risk areas for severe earthquakes, but Clingman said older and unsafe buildings would be damaged regardless of how hard the ground shook.
“Even in the safest part of town, a poorly constructed building would be expected to fare poorly,” he said.
Oregon State University engineering professor Thomas H. Miller estimated that Eugene and Springfield would suffer a minimum of $110 million in economic losses from either a small earthquake of a 6.5 magnitude in the general area, or a major earthquake of 8.5 off the coast. Miller, however, said the report only provided a minimum estimate because it looked at 100 buildings in each city and could not be extrapolated for the rest of the cities’ buildings.
Gary Fritz, University architect for the Facilities Department, said earthquakes are a concern because the University has many historical buildings, including Deady, Villard, Fenton and Friendly, which were built long before seismic activity was taken into account. Fritz said some seismic retrofitting has been done for a few buildings, such as McArthur Court, that were at risk and are frequently used by a large number of people.
A preliminary study for the complete seismic overhaul of the University determined it would cost $50-70 million. Fritz said the Legislature will consider a plan next year to use state funds to help cover the costs of the project, but in the meantime, the campus will just have to accept the risk of earthquakes.
“It’s like the risk of getting on an airplane — you may not get off. You just have to live with a level of risk,” Fritz said.
Nancy Wright, University Housing director of capital improvements and facilities, said that housing initiated a seismic study of its own buildings a few years ago and determined which buildings had not been built to code.
Housing decided to follow a policy that whenever a building needed renovation work, seismic improvements would be included, she said.
Though the Bean complex recently received seismic improvements, Wright said the risk has never been too great to the dorms because of their design.
The buildings “are sturdy because we have all these walls,” Wright said.
A general status of the campus’ seismic health would be hard to ascertain, said Christine Theodoropoulos, an architecture professor who studies the effects of seismic activity on buildings. She said each building behaves differently in an earthquake.
Theodoropoulos did say that older buildings are at risk because they tend to be built with unstable materials that are brittle and “tend to have more catastrophic problems.”
Theodoropoulos said the University should make seismic improvements whenever it can and take steps to ensure that equipment, overhead lights and furniture are secure to prevent injuries sustained inside buildings during an earthquake.

An unpredictable threat
Sue Perry, who holds a masters degree in geology and studied the earthquake risk in the Eugene and Springfield areas for her thesis, said the most damaging earthquake the area could have would come from the Cascadia Subduction fault line approximately 150 miles offshore.
The fault is where the Juan de Fuca plate is slowly moving below the North American plate, and any earthquake from the fault would register no less than eight on the Richter scale.
Other earthquakes in the Eugene area could be crustal earthquakes, triggered by small fault lines in the earth’s crust, or bending moment earthquakes, triggered by faults in the Juan De Fuca plate where it is already beneath the North American plate.
Perry said the last subduction earthquake occurred on Jan. 26, 1700, when written records in Japan registered a tsunami that coincided with the time period of geologic evidence for a huge earthquake on the Oregon coast. If an earthquake of that size were to strike today, the effects would be devastating and not mitigated by the distance to the fault line.
“There would be plenty of energy coming to the local area, even though the fault is so far away,” Perry said.
Using the geological evidence of past subduction earthquakes, Perry said geologists have determined that there have been 12 in the past 7,000 years, and usually occur every 500 years. This timetable has a large margin of error, Perry said, and was not rigid.
“We could expect another one at anytime,” she said.