For more, visit TIME Health. 1  Treating migraines effectively might have gotten a lot easier, according to a new study published this month. 2  Researchers at the Albany Medical Center claim that a new innovative treatment offers chronic migraine sufferers prolonged relief from the debilitating headaches.
That's very fast and it's all because of how deep the water is (thousands of feet) and how much energy the earthquake puts into the tidal wave. So now to directly answer your question, the amount of time it takes for a tsunami to come after an earthquake occurs can be as little as 5 minutes or as long as 24 hours. It just depends on how far away the earthquake was from the coast.
The wave speeds for tsunamis are very high in deep water. The tsunami of December 26, 2004 traveled from near the island of Sumatra to the east coast of Africa in just over seven hours. It was initiated by an earthquake of magnitude 9 off the western coast of northern Sumatra. The wave speed depends upon wavelength and the depth of the water for tsunamis at sea.