Tsunami modeling is not an exact science and tsunamis much larger than anticipated may occur in the future, as occurred in Japan in 2011. Tsunamis may be generated by earthquakes on faults not yet discovered. Tsunamis may be generated by submarine landslides or terrestrial landslides into bodies of water; tsunamis from these sources are not included in the DNR tsunami maps. The ICOS Pre-Disaster Mitigation database includes six levels of tsunami hazard, as shown below. Table 3.1 Tsunami Hazard Levels The ICOS Pre-Disaster Mitigation database automatically opens the tsunami hazard and risk screen for any campus within the tsunami hazard zones listed above, except for the category. Districts may wish to to a tsunami risk assessment if “none” “opt-in” they have reason to believe that a campus may be at risk, even though it does not fall in the categories above. 3.2 Tsunami Risk Assessment: Campus Level For tsunamis, the predominant concern is life safety and the predominant mitigation measure is to prevent or minimize casualties in future tsunamis by immediate evacuation to designated safe locations at elevations well above the anticipated tsunami inundation level before the first arrival of tsunami waves. Campus-level risk assessments have three main elements: Tsunami hazard levels shown above in Table 3.1, Travel distance to the nearest designated safe location, and Travel time to the nearest designated safe location. Designated safe locations for tsunami evacuations are determined locally by emergency management agencies or by districts. Ideal safe locations are at elevations above 100 feet, are as near as possible to campuses, and have travel routes that do not have possible impediments to rapid travel on foot. Travel distance is the path length for walking, not the straight-line distance. Travel times are estimated from the typical walking speeds for students in different age groups, with slower walking speeds for elementary students. Travel times also include 10 minutes for mobilization time–the time between the onset of strong earthquake ground shaking and the beginning of travel to a designated safe area. Estimated walking speeds for tsunami evacuation are shown in the following table.
Tsunami modeling is not an exact science and tsunamis much larger than anticipated may occur in the future, as occurred in Japan in 2011. Tsunamis may be generated by earthquakes on faults not yet discovered. Tsunamis may be generated by submarine landslides or terrestrial landslides into bodies of water; tsunamis from these sources are not included in the DNR tsunami maps. The ICOS Pre-Disaster Mitigation database includes six levels of tsunami hazard, as shown below. Table 3.1 Tsunami Hazard Levels The ICOS Pre-Disaster Mitigation database automatically opens the tsunami hazard and risk screen for any campus within the tsunami hazard zones listed above, except for the “none” category. Districts may wish to “opt-in” to a tsunami risk assessment if they have reason to believe that a campus may be at risk, even though it does not fall in the categories above. 3.2 Tsunami Risk Assessment: Campus Level For tsunamis, the predominant concern is life safety and the predominant mitigation measure is to prevent or minimize casualties in future tsunamis by immediate evacuation to designated safe locations at elevations well above the anticipated tsunami inundation level before the first arrival of tsunami waves. Campus-level risk assessments have three main elements: Tsunami hazard levels shown above in Table 3.1, Travel distance to the nearest designated safe location, and Travel time to the nearest designated safe location. Designated safe locations for tsunami evacuations are determined locally by emergency management agencies or by districts. Ideal safe locations are at elevations above 100 feet, are as near as possible to campuses, and have travel routes that do not have possible impediments to rapid travel on foot. Travel distance is the path length for walking, not the straight-line distance. Travel times are estimated from the typical walking speeds for students in different age groups, with slower walking speeds for elementary students. Travel times also include 10 minutes for mobilization time–the time between the onset of strong earthquake ground shaking and the beginning of travel to a designated safe area. Estimated walking speeds for tsunami evacuation are shown in the following table.