Question

question
which one of the following is true regarding tsunami?
answer
they travel as deep - water waves at speeds greater than surface seismic waves but slower than s waves.
they occur in the open ocean; their wavelengths are many miles or kilometers and their wave heights are only a few feet.
their wave heights decrease and wavelengths increase as they move into shallower water.
they are started by fault - induced, horizontal shifts in the seafloor that suddenly propel great masses of water in opposite directions.
i dont know yet

Explanation:

Tsunamis occur in the open ocean. Their wavelengths are indeed many miles or kilometers long, and their wave heights are only a few feet in the open ocean. As they approach shore (shallower water), wave heights increase and wavelengths decrease. Tsunamis are started by vertical (not horizontal) shifts in the seafloor. Also, tsunami speeds (as deep - water waves) are not greater than surface seismic waves and slower than S - waves.

Answer:

They occur in the open ocean; their wavelengths are many miles or kilometers and their wave heights are only a few feet.