CASCADIAN LANDSLIDES: IMPORTANT EDUCATIONAL CONCEPTS FOR ALL LEVELS OF EDUCATION

Landslides in the Pacific Northwest along the Cascadia Margin are abundant and can be quite devastating. Whether dealing with K-12 students, university students or the general public, certain concepts are important to cover. Everyone needs to know about landslides if one lives in this region. Understanding landslides and processes can save property, if not lives. First concept is that landslides are not normally covered by insurance. Houses hit by landslides or moving downhill on a landslide will not be covered by normal homeowner insurance. Two major triggers cause landslides: rainfall and earthquakes, both which are abundant in this area. Extreme rainfall events can trigger debris flows, mudflows, rock falls, small translational slides and small earth flows. A long buildup of soil moisture in the ground can lead to initiation of large earth flows and translational. Earthquakes can be triggers for rock fall and small earth flows, translational slides and debris avalanches. When triggers are about to happen, land that is prime for landslides (low factor of safety) are susceptible to landslides. Thirdly, reactivation of ancient landslides is a big factor. If land has moved before, it has a higher chance of moving again than land that has never slid. We map old landslides to see susceptible areas. Fourthly, landslides come in many models: different processes and different materials that are moving. Therefore, preventing and mitigating each of them will have different approaches depending upon the process and material. Examples from Oregon and Washington will be used to cover each concept.