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.
Once generated, a tsunami wave in the open ocean can travel with speeds greater than 800 kilometres an hour (500 miles an hour). These waves can travel across the Pacific Ocean in less than one day. Locally generated tsunamis can reach coastlines in just minutes.