In times of threat from natural hazards everyone tries to connect using landlines and mobile phones, networks become severely overloaded.
This has an effect on official warnings. For the government, it is also tricky to get through to the population.
To deal with the problem, the Chilean authorities imported new emergency alert technology in 2011.
The software, developed by Israeli company eVigilo, uses a geo-targeted system that allows the officials to send out mass alerts simultaneously to computers, pagers and mobile phones, as well as radio and television.
Messages are meant to reach millions within seconds – even if all networks are busy.