Question

What type of warning systems do places have to tell people there are going to be tsunamis?

Answer 1

There must be an earthquake detector in place to detect any earthquakes off the shores in the oceans. This system can be a regional or local system, and although the system is fallible the margin of error is very small.

Sometimes though the earth quake/movement is too close to shore to detect it in time, and people get caught in it as a result.

There also needs to be a universal warning signal that actually tells people that the tsunami is coming.

I hope this helped.