A tsunami is a gigantic sea wave, also called a seismic sea wave. They are very tall and have destructive power. A tsunami forms when there is a sudden ground upsurge and quickly followed by a drop.
Through this action, the water column is pushed high above the average sea level. Volcanic tsunamis can result from violent underwater seismic explosions. They can also be caused by caldera collapses, which are tectonic plate shifts from volcanic activity.
A massive flank failure into a water source or a pyroclastic flow discharging into the sea. As this huge wave starts forming, it moves in a vertical direction and gains unbelievable speeds while in deep waters and can reach final speeds of as fast as 650 mph. even in shallower water, it can still reach speeds of up to 200mph.
These giant waves travel over the continental shelf to where they crash into the land. This kinetic power doesn’t decrease once they have hit land though, as there is an extreme amount of energy once the water starts traveling back towards its source. Approximately 5 percent of all tsunamis are formed from volcanic activity and nearly 16.9 percent of volcanic deaths occur from tsunamis.