INCREASING EARTHQUAKE RESILIENCY TO OREGON'S INFRASTRUCTURE

The Pacific Northwest’s extreme disaster is a magnitude 9 earthquake on the Cascadia subduction zone, which would produce minutes of strong ground shaking, coastal subsidence, landslides, liquefaction, lateral spreads, and a coastal tsunami. Seismic provisions in Oregon’s building codes were first explicitly adopted in 1993. In contrast, Oregon’s lifeline infrastructure is not governed by a uniform set of design and construction codes. Much of the existing infrastructure has been constructed with severe seismic design deficiencies. New critical infrastructure is often constructed without adequate seismic provisions. To minimize extensive direct earthquake damage, indirect losses and untold ripple effects, substantial improvements to infrastructure are necessary.

To promote resiliency of energy and telecommunications infrastructure, progress has been made in three areas: 1) technical, 2) political, and 3) regulatory. Examples of each, respectively, are: 1) earthquake hazard maps for lifelines along Interstate 5 for northern Oregon have been developed 2) new policies have been adopted in the 2009 State Natural Hazard Mitigation Plan, which was approved by FEMA and adopted by the Governor, and 3) critical infrastructure security & reliability audits of utilities network systems are made by OPUC. Another example that combines the three areas is the 2008 critical infrastructure forum, which was co-sponsored by DOGAMI, OPUC, and several private utilities that involved the state’s political leadership. Additional pre-disaster mitigation activities are underway.

We recommend that: 1) critical infrastructure in high hazard areas be evaluated for their seismic risk, and 2) critical infrastructures that are at high risk and that have significant ripple effects be mitigated. To enhance and expedite progress on infrastructure resiliency, we recommend combining technical, political and regulatory approaches.