Magnetic hovering houses the future of earthquake-proofing homes?

The video discusses modern earthquake proofing systems, focusing on base isolation bearings that allow buildings to move without damage. Arx Pax has developed a buffer system using water or gas to protect homes from lateral movement. Henderson proposes a new system using electromagnetics to lift houses during earthquakes, linked to the US Geological Survey's ShakeAlert system. This system uses sensors near fault lines to detect earthquakes, allowing houses to hover for up to 90 seconds, providing residents with early warnings.

What is the significance of the 90 seconds hover time in Henderson's system?

Explain how the ShakeAlert system contributes to earthquake preparedness.