Communicating Hazard Location through Text-and-Map in Earthquake Early Warnings: A Mixed Methods Study

The purpose of this research was to examine the effect of presenting hazard location in different formats on key warning message outcomes - understanding, personalizing, believing, deciding, and milling. We conducted two studies using experiment and focus group methods. In the experiment, we compared a standard ShakeAlert earthquake early warning message, which merely implied location, to three enhanced messages that communicated information about the earthquake epicenter via text, map, or a combined text-and-map format. Focus groups explored reactions to warning messages accompanied by different types of maps. Overall, the standard ShakeAlert message was associated with worse message outcomes compared to messages that explicitly stated the hazard location; communicating hazard location via text was associated with better message outcomes than the map or combined text-and-map format. Although participants preferred the combination text-and-map format, the text format was associated with significantly better message outcomes. Findings revealed that providing specific hazard location information leads to improvements in message outcomes; however, the format in which the information is communicated via text is the best strategy.