If you're close to the epicenter there's no way for any app to give you advance warning. Any app is going to make use of the fact that internet messages travel

If you're close to the epicenter there's no way for any app to give you advance warning. Any app is going to make use of the fact that internet messages travel faster than earthquakes, so the farther you are from the epicenter the more warning you'll get. Close to the epicenter is going to be no warning regardless of whose app you use.