Most tsunami are caused by earthquakes on subduction zones. The map below shows the source locations of tsunamis: 1650 B.C. to 2010 A.D. Note that most occur on subduction zones.
NOAA has two warning centers - National Tsunami Warning Center and the Pacific Tsunami Warning Center. The National Tsunami Warning Center (formerly the West Coast and Alaska Tsunami Warning Center (WC/ATWC)) was founded in Palmer, Alaska in 1967 after the 1964 Alaskan earthquake and tsunami. The Pacific Tsunami Warning Center, located in Ewa Beach, Hawaii, was founded in 1949, following the 1946 Aleutian Island earthquake and a tsunami.