Mexico City has made available an earthquake application that sends alerts direct to phones as soon as a tremor happens. Aplicación Alerta Sismica del DF is tied to remote monitoring stations that detect and send signals up to a minute before the tremors reach the capital. The capital is plagued by earthquakes, with one or two per year impacting the city that is built upon a dry, but unstable, former lake bed.
At present the app is only available for BlackBerry phones. The city is working to connect the sensors to sirens, and may add additional mobile platforms in the future.