TerraPulse: Planetary-Scale Seismic Early Warning

Design a global early-warning system for seismic activity using a mesh of 1 million low-cost IoT sensors. The system must distinguish between 'noise' (traffic, construction) and 'p-waves' (earthquake precursors) at the edge, transmit high-priority alerts to a central processing hub in under 50ms, and broadcast emergency alerts to 1 billion mobile devices within 2 seconds of detection. The system must be resilient to localized infrastructure collapse (e.g., if the local internet goes down during the quake).