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State and local officials participated recently in Cascadia Rising, an emergency operation testing Oregon鈥檚 preparedness for a Cascadia Subduction Zone earthquake 鈥� aka a 鈥淏ig One.鈥�

A heightened appreciation for the danger lurking offshore has spread to officials in Oregon鈥檚 coastal communities, who face several daunting challenges associated with replacing their critical facilities. The dilemma facing the community of Yachats (population: 690) is just one, illustrative example.

Nearly all of Yachats is located within the state鈥檚 most updated Tsunami Inundation Map of the area, including its water plant, wastewater plant, library and city hall. This means that if plans are made to replace the buildings, they would have to be built outside the city proper.

Seismic building codes have been on the books in the Northwest since the mid-1970s, though many coastal buildings were built under earlier codes. The station house for the Yachats Rural Fire Protection District was built in 1949, before the state鈥檚 first building code was enacted.

In 1995, the Oregon Legislature passed Senate Bill 379, restricting the construction of critical facilities and special-occupancy structures in tsunami flooding zones. For guidance, the Oregon Department of Geology and Mineral Industries (DOGAMI) has created Tsunami Inundation Maps for the entire coastline. An appeals process is the only way to overcome the restriction to build within the zone, and DOGAMI hasn鈥檛 issued one in the 21 years the law has been in effect.

In Yachats, the site chosen for a new fire station was found to be located in the most up-to-date inundation zone mapping. This left the community with several options, including pushing for additional seismic mapping, or purchasing different property in town.

鈥淏ut, you know, Yachats doesn鈥檛 have much space between the water and the mountain,鈥� said Ian Madin, DOGAMI鈥檚 chief scientist.

DOGAMI has learned a lot about how buildings perform in extreme weather from the 2011 earthquake and tsunami in Japan, Madin said. Lately, he added, coastal communities have been more open to working with the state.

鈥淲hen I first started talking about Cascadia Subduction Zone earthquake, I spent all my time convincing people that it was real and that it was something they should pay attention to,鈥� he said. 鈥淎nd now when I go to meetings, their question is: 鈥楬ow do pay for these changes we need to make?鈥� 鈥�

Madin said some of the current interest could be the result of $175 million available in this year鈥檚 Seismic Rehabilitation Grant program.

The state has outlined several target dates for seismic upgrades to be completed, including 2022 for all those to emergency facilities and 2032 for those to education facilities. The median year of construction for a K-12 education building in Oregon is 1962, according to a 2007 DOGAMI survey of the state鈥檚 2,187 school buildings. The median year of construction for fire and police buildings is 1974.

DOGAMI estimates that the likelihood of a magnitude 9 Cascadia Subduction Zone earthquake occurring in the next 50 years is 10 to 15 percent. The likelihood of one hitting local fault lines is between 35 and 40 percent.