Tsunami Tsunamis consist of a series of long-period waves characterized by very long wave length(up to 100 km)and high speed (up to 760 km/hr)in the deep ocean Because of their large wave length, tsunamis are shallow-waterto intermediate-water waves as they travel across the ocean basin They only become DANGEROUS. when reaching coastal areas where wave height can reach 10 m Tsunamis originate from earthquakes, volcanic explosions, or submarine landslides Tsunamis consist of a series of long-period waves characterized by very long wave length (up to 100 km) and high speed (up to 760 km/hr) in the deep ocean.  Because of their large wave length, tsunamis are shallow-water to intermediate-water waves as they travel across the ocean basin.  They only become DANGEROUS, when reaching coastal areas where wave height can reach 10 m.  Tsunamis originate from earthquakes, volcanic explosions, or submarine landslides. 7-5 Tsunami