Question: how long did it take for the tohoku tsunami to arrive
Answer: The earthquake took place at 14 : 46 JST ( UTC 05 : 46 ) around 67 km ( 42 mi ) from the nearest point on Japan 's coastline , and initial estimates indicated the tsunami would have taken 10 to 30 minutes to reach the areas first affected , and then areas farther north and south based on the geography of the coastline .