"Wind-generated waves usually have periods (time between crests) of 5 to 20 seconds, while the time between these peaks tsunamis are usually between 5 minutes and an hour.

Wind-generated waves break as they shoal and lose energy offshore, while tsunamis act more like a flooding wave. A twenty foot tsunami is a twenty foot rise in sea level.

Tsunami waves are distinguished from ordinary ocean waves by their great length between peaks, often exceeding 100 miles in the deep ocean. "

Citation source: http://wcatwc.arh.noaa.gov/characteristics.htm

http://www.publicaffairs.noaa.gov/grounders/tsunamis.html