Final answer:
The distance between tsunami wave crests with a speed of 600 km/h and arrivals every 15 minutes is 150 km. Tsunamis can be detected using seismographs and warned against through channels like sirens.
Step-by-step explanation:
To determine the distance between tsunami wave crests when the waves travel at 600 km/h and a wave crest arrives every 15 minutes, we can use the formula distance = speed × time. Given a speed of 600 km/h and a time of 15 minutes (or 0.25 hours), the calculation would be 600 km/h × 0.25 h = 150 km. Therefore, the distance between the wave crests of the tsunami at sea would be 150 kilometers. It is also important to note that tsunamis can be detected using seismographs, and warnings can be issued through various channels such as loudspeakers, social media, and sirens. These early warning systems can provide crucial time for evacuation and potentially save lives.