“We ran outside and waited for it to come”: Resident experiences in response to a false earthquake early warning

Abstract

Ridgecrest, CA, experienced the Searles Valley earthquake sequence in 2019 and a “false” earthquake alert in 2020, providing a unique opportunity to examine the effects of earthquake experience on future responses to informational cues to action (i.e., earthquake alert), as well as reactions to a “false” alert. We conducted in-depth interviews with 41 residents using the protective action decision-making model as a theoretical framework. Interviewees reported a variety of environmental cues that signaled the onset of an earthquake, including sensing a foreshock, hearing the earth rumble, hearing objects fall to the floor and break, and observing unusual animal behavior. Fewer individuals received social cues to action. More individuals reported performing “drop, cover, and hold on,” and fewer reported standing in a doorway in response to the 2020 alert than had done so in the prior 2019 earthquake. Several respondents reported maintaining protective actions well after the “false” alert was issued, and many waited more than 5 min before determining there was no threat present. Prior experience of the 2019 earthquake series affected perceptions of the earthquake alert and what actions to take; however, there was limited knowledge of how the ShakeAlert system worked to monitor, detect, and model earthquakes via earthquake early warning to persons at risk. Findings indicate there is a need for additional public education about ShakeAlert-powered earthquake early warning, including how far in advance one can expect to receive an alert, as well as the protective actions one should take and when to take them.