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Examination of Usage Rates for the Multi-Hazards San Diego County Emergency App to Improve Earthquake Early Warning

Description: 

One of the global targets of the Sendai Framework for Disaster Risk Reduction is to ‘substantially increase the availability of and access to multi-hazard early warning systems and disaster risk information and assessments to people by 2030’. To accomplish this, the systems need to be tailored to user specific needs, have a broad scope of communication channels, and disseminate critical timely hazard information to affected communities. The efficacy of these systems, including earthquake early warning (EEW), requires integrating ideas from a range of stakeholders, including government, academia, and industry. A key problem for smartphone applications is attrition, with a recent study showing that an earthquake detection app had high attrition rates of >90% within a year. In this study, we investigated the usage over time of the multi-hazard warning smartphone app SD Emergency, developed by the San Diego County Office of Emergency Services and Peraton, its IT provider. As the only multi-hazard smartphone app in the US that delivers ShakeAlert-powered EEW alerts, we hypothesized SD Emergency would have lower attrition rates. By comparing install and uninstall data for Android and iOS, we found that the app maintained a retention rate above 50% over the past 6 years. This was based on stable uninstall rates which we interpret as due to regular alerting (~70 alerts per year). Yet even on days with no alerts, there were twice as many installs as uninstalls. There were also frequent spikes in install rates during both natural (e.g., earthquake, fire, weather) and anthropogenic (e.g., boil water notice, oil spill) events. Fire accounted for 55% of all alerts and similarly accounts for ~60% of peaks in the app install rate. Install rates increased dramatically as the number of alerts per day increased, without commensurate increases in the uninstall rate. Considering that earthquakes accounted for <1% of alerts, the multi-hazard alerting strategy substantially improves the likelihood people will retain EEW capabilities, increasing the efficacy of alerting and maintaining critical communication pathways.

Session: End-to-End Advancements in Earthquake Early Warning Systems [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Michael

Student Presenter: No

Invited Presentation: 

Authors