As it turned out, smartphones can partially fulfill the role of seismic sensors. Of course, the accuracy of smartphone sensors is significantly inferior to special seismic equipment, but GPS receivers are quite able to fix the surface displacement, characteristic for strong earthquakes.
In this case, the user community of the application acts as an alert system that warns about the dangers of other users. So, for example, if 5000 people in one area have an earthquake recorded by an smartphone and this information has arrived at the analytic center, then after prompt processing it can be immediately transferred to another area and warned about the imminent disaster.
It is quite natural that this system has its drawbacks associated with the limited capabilities of smartphone sensors. In particular, it will not be able to fix weak earthquakes and works with the strength of the earthquake from 7 points and above.
However, in countries with high seismic activity that can not afford the creation of a modern earthquake warning system, the development of American scientists will certainly be in demand.