Tsunami warning system

Tsunami warning system or TWS detects tsunamis and issues warnings to prevent loss of life and property. It consists of two equally important components: a "network of sensors" to detect tsunamis and a "communications infrastructure" to issue timely alarms to start evacuation before the big waves reach the land to let the people to rush to safety.
There are two distinct types of tsunami warning systems: "international" and "regional". Both of those systems depend on the fact that "tsunami waves" travel, approximately, 15-30 times slower than "seismic waves".