Assessing potential tsunami vertical-evacuation practices: A study of four cases in Chile using virtual reality and GIS

Tsunami vertical-evacuation (TVE) can save numerous human lives when horizontal evacuation is not feasible. A key topic in TVE planning is the optimal placement of shelters, which is typically studied using a top-down approach. Recently, virtual reality (VR) has become an emerging tool to support disaster risk reduction and emergency response training. While VR has been applied to visualise tsunami flood zones and evacuation routes, no studies have used VR to assess the evacuees' shelter choices during emergencies or to examine the optimal 'siting' of TVE buildings. To address this gap, this study introduces a user-focused VR evacuation experiment to automatically collect the shelter preferences of 435 participants regarding existing buildings that might serve as TVE shelters in four case studies in Chile.

Complementary, we used questionnaires to collect information about the participants' tsunami evacuation expertise, awareness, and the factors that led to their shelter selection. Lastly, we used GIS to examine the location characteristics of the selected buildings. The results showed that 50 buildings gathered at least two preferences, with a large diversity of heights (five to 34 storeys) and placements (from 52 to 2774 m from the coast). Height is the most critical factor when choosing a building for TVE (53.1 % of the preferences), and most of them are residential (62.7 %). Additionally, 67.2 % of the participants had experienced real-world evacuations, and the average evacuation rate during the last emergency in each of the case studies was 43.8 %. While most participants declared affirmative response rates about the perceived tsunami threat (above 60 %), low specific knowledge regarding evacuation plans might discourage protective actions in future tsunami emergencies.