Question: Would you be able to know if a tsunami came?

Ollie Otter answered on 4 Mar 2020:

More or less. Tsunamis are mostly triggered by earthquakes and earthquakes can be measured with seismic equipment. So if an earthquake is measured near the coast or under the seabed, then tsunami warnings can be given.
Basically, a tsunami is a very big wave. If there are buoys that can measure waves in the sea area where the earthquake was, then we can probably detect the tsunami waves and say with more certainty that a tsunami is on its way to the coast. But even with all that equipment it is still difficult to say with 100% certainty that a tsunami is on the way.