An assessment of educational tsunami evacuation map designs in Washington and Oregon

Abstract

Educational tsunami evacuation map brochures in Washington and Oregon have been developed locally, resulting in significant differences between the types of tsunami hazard information they include. This paper identifies six tsunami hazard information types present in 38 brochures in Washington and Oregon: (1) tsunami hazard zone, (2) road network, (3) assembly areas, (4) evacuation guidance, (5) infrastructure, and (6) terrain. It compares and contrasts these information types in the maps and text of six of the brochures, including a proposed design standard in Oregon. Design differences of all 38 brochure maps are then organized using principles of cartographic abstraction, which describe mapmaker decisions about selection, generalization, and symbolization of information. We further use this framework to situate the information content of a new interactive Google Maps tool in Oregon. Our assessment identifies limitations of current tsunami hazard information that may be relevant to improving tsunami education. In theory, more advanced evacuation map tools can play an important role in reducing the limitations of tsunami hazard information relevant to the public. The new Google Maps tool addresses few of these limitations. Recognizing how map-making decisions define the underlying information content of evacuation maps can facilitate much needed future evaluations and developments in evacuation map design.