Least Cost Path Analysis: Tsunami Evacuation

Undergraduate #223
Discipline: Ecology Environmental and Earth Sciences
Subcategory: Geosciences and Earth Sciences

Priscilla Baltezar - Humboldt State University
Co-Author(s): Ana Molina and Sam Ureel, Humboldt State University, Arcata, CA

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Municipal safety in local communities is inextricably connected to the natural environment in which that community resides. It is essential to assess the possible hazards within any major or minor municipal zones in order to protect environmental and public interest. Northern California faces significant earthquake and tsunami risks due to the presence of major subduction plates (Pacific Northwest Seismic Network [PNSN], n.d.). Impact hazard assessment allows communities to develop a more effective safety plan and to reduce the damage that an earthquake event may pose in a coastal community. An effective safety plan would need to include the most efficient evacuation routes in the event of a tsunami event. I hypothesize that GIS analysis will be an effective tool for evaluating the viability of different tsunami evacuation routes. I used the Spatial Analyst Toolbox in ArcMap 10.1 to model an evacuation route from one location in Arcata that was susceptible to flooding in the event of a tsunami. With the software, I developed an algorithm that could take different data layers and assign weighted costs to slope, elevation, and tsunami inundation to determine the ‘least cost path’ from a given location to an area of safety. The origin point was set north east of Humboldt Bay and the program showed a final destination to safety ending south east of Humboldt Bay at a preferred elevation point. The purpose of this study was to explore the applications of the Spatial Analyst toolbox in quantifying evacuation during an earthquake tsunami event. A significant challenge included being able to quantify the extent of damage and realistically applying it to a more standardized safety plan. In order to more easily apply the model one should take into account the variability in the location of residents within an area that is at risk. This study revealed that GIS analysis has the potential to contribute greatly to evacuation planning, but that there are areas where the technique could be better developed to take into account the complexity of local communities. (Key Terms: Euclidean distance, Spatial Analyst, Raster, GIS, Hazard Planning, DEM, Spatial Analyst).

Funder Acknowledgement(s): Humboldt State University

Faculty Advisor: Laurie Richmond,