Structures predating 1974, when Oregon enacted its first statewide building code, would suffer the worst damage in a 9.0-magnitude earthquake. Buildings constructed after 1993, when western Oregon adopted its first seismic standards, are considered the most likely to withstand a severe earthquake. The map shows which buildings in the tri-county area were built in each era. The data from Metro regional government do not reflect potential seismic upgrades or renovations.