Earthflow Underground turns a utility's existing GIS / OMS / SCADA / AMI data -- fused with 70+ authoritative open datasets (SSURGO, FEMA, USGS, NLDN, IEEE) -- into a 7-day living digital twin. A 15-module Physics AI engine + Cirra agentic AI returns a per-segment Asset Health Index (1-5), Remaining Useful Life, and a recommended action (REPLACE / REPAIR / RETIRE / DEFER / MAINTAIN) -- defensible to FERC/PUC. >=70% top-50 precision; $5-15M deferrable capex per 500-1,000 mi; <2-yr payback.