ShakeAlertLA alerts you that an earthquake has been detected and that you may soon feel shaking. You can also use this app to prepare for an earthquake, get details on recent earthquakes, and find help after an earthquake. This app is brought to you by Mayor Eric Garcetti and the City of Los Angeles, and built on the ShakeAlert system developed by the U.S. Geological Survey.
Version 1.1 adds a new feature based on feedback from the ShakeAlertLA community. The "Recent earthquakes" screen now displays earthquakes of magnitude 3.0 and above in the past 30 days for the continental United States.
More information and a tutorial is at https://earthquake.lacity.org/shakealertla.