What amplified seismic event creates transoceanic tsunami waves following megathrust earthquakes?

💡 Explanation

When a megathrust earthquake occurs, seafloor vertical deformation occurs because it rapidly uplifts or down-drops vast areas on shallow inclined subduction zones generating large-scale water displacement. Therefore transoceanic tsunamis result, rather than rebound mechanisms or vent displacement whose local disturbances dissipate without transoceanic scale effects.

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