Abstract
Android's Earthquake Alert (AEA) system provided life-saving early warnings to millions during the M6.2 Marmara Ereğlisi, Türkiye earthquake on April 23, 2025. This event, the largest in the region in 25 years, served as a critical real-world test for smartphone-based Earthquake Early Warning (EEW) systems. The AEA system successfully delivered alerts to users with high precision, offering over a minute of warning before the strongest shaking reached urban areas. This study leveraged Large Language Models (LLMs) to analyze 560 public social media posts from the X platform, extracting 42 distinct attributes related to user experience and behavior. Statistical analyses revealed significant relationships, notably a strong correlation between user trust and alert timeliness. Key findings indicate that alerts received before shaking, clear information, and audible notifications significantly increased the likelihood of active protective responses and enhanced perceived usefulness and future trust in the system. Conversely, annoyance and perceived inaccuracy led to inaction and diminished trust. The study highlights the profound impact of smartphone-based EEW in mitigating seismic risk, providing actionable insights for optimizing alert design, public education campaigns, and future behavioral research to improve the effectiveness of such systems in seismically active regions.