Question

why Tsunami passes and noticed at sea

Answer 1

Tsunamis are caused when there is disturbance far below the ocean such as a volcano, earthquake, or land collapsed. An earthquake in the water is the most common puncture for a tsunami, but not just a submarine earthquake causes a tsunami. Earthquakes need to be large enough earthquakes of about 7.0 magnitude or larger may also cause Tsunami.
Underwater earthquakes apply to oceans and continental plates, where large areas of the earth's crust, reject each other and form pressure. The need for pressure on the earth's crust causes the continental plate slip or is also recognized as Tektonik movement. The vertical movement of the earth's crust which may result in the seabed rising or falling suddenly, resulting in a disruption of the water balance above it. This resulted in the flow of sea water energy, which when it reaches the shore becomes a big wave so that the occurrence of Tsunami.


I hope this help :3
-Fona