Describe a top-down and bottom-up approach to tsunami evacuation planning.

• A. Top-down relies on local drills, bottom-up relies on satellites.
• B. Top-down uses national hazard assessments, sea-level rise data, and siren networks; bottom-up emphasizes community drills, local knowledge, and evacuation routes.
• C. Top-down ignores community input; bottom-up ignores warning systems.
• D. Top-down is only about building codes.

Answer: (B)

Top-down and bottom-up approaches differ in where planning authority and information come from. In a top-down tsunami evacuation plan, national or regional authorities drive the process. They compile hazard assessments, sea-level rise projections, and establish warning networks such as sirens, then translate that guidance into evacuation protocols for communities. The aim is consistency and rapid dissemination of warnings across large areas.

A bottom-up approach centers on communities and local knowledge. It prioritizes practical drills organized by local leaders, input from residents on familiar routes and obstacles, and adapting evacuation plans to local geography and demographics. This ensures routes are actually usable and that vulnerable groups are prepared.

A strong plan blends both: centralized hazard data and warning infrastructure support local participation and tailored evacuation routes. The other options misstate this balance—for example, top-down shouldn’t be about local drills, bottom-up isn’t about ignoring warning systems, and top-down isn’t only about building codes.