Dependent on the distance of the tsunami from its source, it may be classified as a:

• Local tsunami:

A local tsunami is one that originates from within about 100 km or less than 1 hour tsunami travel time from the impacted coastline. Local tsunamis can result in a significant number of casualties since authorities have little time to warn/evacuate the population. 

• Regional tsunami:

A regional tsunami is one that is capable of destruction in a particular geographical region, generally within 1,000 km from its source. Regional tsunamis can arrive to affected coastlines within 1-3 hours of being generated, however, as with local tsunamis, due to the limited warning time they can still prove very destructive and deadly.

• Tele-tsunami/Ocean-wide tsunami/Distant tsunami:

A tsunami originating from a source, generally more than 1,000 km or more than 3 hours tsunami travel time from the impacted coastline is called an ocean-wide or distant or tele-tsunami.  These tsunamis are less frequent, but more hazardous than regional tsunamis, as they usually start as a local tsunami that causes extensive destruction to a shoreline near the source, and the waves continue to travel across an entire ocean basin with sufficient energy to cause additional casualties and destruction on shores more than a 1,000 km from the source. These tsunamis have the ability to cause widespread destruction, not only in the immediate region but across an entire ocean.  All ocean-wide tsunamis have been generated by major earthquakes.