Understanding the Multimodal Evacuation Behavior for a Near-Field Tsunami

This paper presents an agent-based tsunami evacuation modeling (ABTEM) framework in Netlogo to analyze the impact of various multimodal evacuation behaviors on life safety for a near-field tsunami. The objective of this work is to investigate how: milling time, choice of modes (i.e., walking and automobile), and critical variables involved in an evacuation scenario (e.g., walking, driving speed), affect life safety. Using the city of Seaside, Oregon, which is one of the most vulnerable cities on the Oregon coast, as a study site, different evacuation scenarios are included in the model to assess the impact of parameters involved on the mortality rate in a tsunami evacuation event. The results show that: choice of evacuation mode strongly and non-linearly influences the expected number of casualties; use of vehicles leads to the creation of congestion and bottlenecks, and thus, higher mortality rate; the mortality rate is strongly correlated with milling time; and the mortality rate is sensitive to the variations in average walking speed of the population. The results will help emergency managers, community leaders, and city and state agencies in their decision-making process for creating effective and efficient evacuation plans to increase life safety and community resilience.