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Eugene -Springfield Area Natural Hazards Mitigation Plan 2. Hazard Descriptions information about possible earthquakes on Oregon faults. This model presents an expected level of damage associated with an earthquake with a 2-percent chance of occurring in the next 50-years. This probabilistic model suggests the Eugene - Springfield area can expect the partial collapse of weak buildings and the movement of unsecured wood -frame houses. While all earthquakes possess the potential to cause major damage, subduction zone earthquakes pose the greatest danger due to the severity, duration, and extent of ground shaking. Within Oregon, a major CSZ incident could generate an earthquake with a magnitude of 9.0 or greater, likely resulting in significant damage and loss of life in Eugene -Springfield. Another way to assess the probability of an earthquake for Oregon communities west of the Cascades is to consider the CSZ incident independently. According to the Oregon NHMP, the reoccurrence interval period for the largest of the CSZ earthquakes (magnitude 9.0+) is 530 years with the last incident occurring 320 years ago in January of 1700. The probability of a 9.0+ CSZ incident occurring in the next 50 years ranges from 7 - 12%. Notably, 10 - 20 "smaller" magnitude 8.3 - 8.5 earthquakes identified over the past 10,000 years affected only the southern half of Oregon and northern California. The average reoccurrence interval period for these incidents is roughly 240 years. The combined probability of any CSZ earthquake occurring in the next 50 years is 37 - 43%. This puts the odds of having a significant (magnitude 8.0+) earthquake from the Cascadia fault line at roughly one in three over the next 50 years.29 Eugene -Springfield categorizes the probability of a CSZ incident as moderate and the probability of intraplate and crustal earthquakes as low. Given the potential for damage and the probability of occurrence, Eugene -Springfield is primarily focused on a potential CSZ incident for earthquake mitigation planning purposes. 2.3.6 Vulnerability and Capacity Assessment In 2014 the Cities of Eugene and Springfield conducted a Regional Climate and Hazards Vulnerability Assessment to inform the prior edition of the NHMP. The Project Team, for this edition, determined the vulnerabilities listed below generally remain valid for preparing this edition. The assessment team met with local and regional experts in the communication, drinking water, electricity, food, healthcare, housing, natural systems, public health, public safety, transportation, stormwater, and wastewater sectors. The assessment identifies the following specific earthquake -related vulnerabilities: 28 United States of America. Oregon National Guard. Office of Emergency Management. Oregon Natural Hazards Mitigation Plan: Region 3-Mid/South Willamette Valley. Salem, OR: Office of Emergency Management, 2015. 534-46. 2-16 January 2020