Earthquake Early Warning from Cheap Accelerometers — Design Blueprint: Dedicated-Node and Phone Networks with Latency, Blind-Zone, and Density Rules

DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. Build-ready design blueprint derived from 'Earthquake Early Warning from Cheap Accelerometers: An Honest Latency-and-Geometry Budget, a Blind Zone, and a Priced Verdict' (DOI: 10.5281/zenodo.24108595). Specifies a dedicated-node network (noise density 25 ug/sqrtHz, about US$100 per node, 5-sigma trigger with two-node coincidence) at about one node per 100 km2, delivering 9.4 s of public warning at 50 km and 23.5 s at 100 km for a magnitude 6.5 event at 10 km depth, with phone nodes (200 ug/sqrtHz) as a supplement. Includes bill of materials (unit costs only where the source states them), siting and density sizing rules, integration, installation, calibration and commissioning against the latency budget (dedicated total 3.5 s public, 1.8 s local), operating envelope, maintenance, failure modes and non-claims. Printed failure regimes at full size: a blind zone of about 15 km (dedicated) to 25 km (phone) where no warning is possible at any density; density beyond about 1 per 100 km2 buys almost nothing (0.37 s, then 0.04 s) — latency is the lever; local actuation cuts the dedicated blind zone to 7.1 km. All numbers are reproduced by the deposited compute.py.