How do earthquakes cause tsunamis to occur?
Earthquakes have the potential to generate a tsunami, but how exactly? When the earthquakes cause a disturbance in the sea floor that is when earthquakes cause a tsunami. If this happens, a tsunami can reach in only a few minutes especially if it's a major earthquake. 95% of the time tsunamis are caused by earthquakes, but unfortunately even if the magnitude and location is known a tsunami cannot be accurately predicted. Although, since an earthquake is too small to create a tsunami by itself it may trigger an undersea landslide which is quite capable of generating a tsunami. The tsunami is usually most intense when close to the earthquake which means as waves spread from the epicenter (the point on the earth's surface vertically above the focus of an earthquake) in a typical arc-shaped pattern, their energy also spreads out.
In 1946, a tsunami hit without warning, killing over 170 people. It originated from the Aleutian Islands so it lasted about 5 hours.
Tsunami Travel Time
This map shows how many hours it would take for a tsunami generated anywhere on the rim of the Pacific basin to reach Hawaii. The dots indicate the locations of earthquakes that have generated tsunamis which have affected Hawaii. A tsunami produced by an earthquake on the coast of Chile will reach the Hawaiian Islands in about 15 hours, while one that originates in the Aleutian Islands will arrive in 4.5 to 5.5 hours.