Smartphones can be used as early warning systems for earthquakes

The video explains how ground movement during earthquakes can be detected and used to issue warnings, especially for earthquakes with a magnitude of 7 or greater. It highlights the role of crowdsourcing, where a small percentage of people in an area can contribute information via their smartphones to provide early warnings.

What percentage of people is needed to contribute information for crowd-sourced early earthquake warnings?

What devices can contribute information for early earthquake warnings?