EXPERT’S RISK PERCEPTION OF A MAJOR EARTHQUAKE EVENT IN THE CASCADIA SUBDUCTION PLATE BOUNDARY AREA

The Cascadia Subduction Zone (CSZ) is a tectonic plate boundary that is located about 64 to 128 kilometers off the west coast from Northern California to Vancouver Island, British Columbia (Cascadia Region Earthquake Workgroup, 2013). Subduction faults are on a cycle of a pressure build up then quick release, materializing as a megathrust earthquake. These faults have the potential to produce earthquakes of the highest magnitude. Paleoseismic studies and Native American oral history have proved that the last CSZ earthquake occurred in 1700 and likely had a magnitude of 9.0 (Finkbeiner, 2015, Nelson et al., 2006). Most probability analyses suggest that there is a 7 to 15% chance of a CSZ earthquake in the next 50 years (Lewis et al., 2007, Buylova et al., 2019) Is the Pacific Northwest prepared for a high magnitude earthquake and tsunami event? The purpose of the study is to document if and how individuals, communities, and town and state governments are preparing for the CSZ megathrust earthquake. A local seismology expert, two members of different emergency preparation and response groups, and a town official were interviewed. The interviews were recorded, transcribed, and compared. The six most commonly mentioned themes between the participants were identified and discussed. These themes include: (1) public awareness; (2) what motivates people to prepare; (3) community building; (4) cannot rely on government support; and (5) failing infrastructure and utilities. All participants believed that there is a high level of awareness of the geohazards involving the CSZ, however, awareness does not equate to taking preparation measures. Participants revealed different levels of risk perceptions and beliefs on how much individual preparation is necessary. Interpreting the interview data in our current societal context suggests that environmental justice and vulnerable populations’ needs are important issues in the context of a CSZ earthquake and tsunami event.