How good are these things against false alarms?
Imagine a bunch of teenagers get together and all pound their ceiling near the sensor.
From a previous post:
Elevators can stop at the next floor and open their doors.
Nuclear power plants can insert their control rods.
Toll bridges can close their gates so no more cars go onto the bridge.
Same for tunnels.
Gas valves can shut off.
Turbines can slow down or stop.
Sirens can sound in tsunami zones.
Active seismic control systems can apply tension.
Bank vaults can lock.
Automatic security systems can be notified to prevent a flood of false alarms.
Data centers can sync their HDDs and start their diesel generators.
Fire station roll up doors can automatically open, so they don't jam closed in the quake.
Commuter trains can slow down and stop.
Approaching aircraft can be delayed or diverted.
Traffic lights can go to all-red.
And it's just a bunch of teenagers pounding on the ceiling.