ShakeAlert gives zero warning to people near the epicenter who need it most

The ShakeAlert earthquake early warning system, operational across California, Oregon, and Washington, detects earthquakes using seismometer networks and sends alerts to phones before shaking arrives. The fundamental physics limitation is that people closest to the epicenter, who will experience the strongest and most destructive shaking, receive the alert last or not at all. If an earthquake originates directly beneath you, the seismic waves reach you at the same instant they reach the nearest seismometer, meaning there is literally zero seconds of warning. Even for people 10-20 miles from the epicenter, the alert processing time (detecting the quake, characterizing it, generating the message, transmitting it) consumes most or all of the available warning window. FEMA's Wireless Emergency Alert (WEA) system adds additional delays, often more than 5 seconds, meaning WEA-based alerts frequently arrive after shaking has already started. The people who receive useful warning (10-60 seconds) are those far enough from the epicenter that shaking is moderate anyway. The system works best where it is needed least and fails where it is needed most. This problem persists because the speed of light (data transmission) can outpace seismic waves only over distance, and no amount of engineering can change the physics of near-field warning times.