Answer:
Most tsunami damage and destruction is caused by flooding, wave impacts, erosion, strong currents, and floating debris (e.g., trees, structures, vehicles, and other things that can act like battering rams). The water can be just as dangerous, if not more so, as it returns to the sea, taking debris and people with it.
The majority of deaths associated with tsunamis are related to drownings, but traumatic injuries are also a primary concern. Injuries such as broken limbs and head injuries are caused by the physical impact of people being washed into debris such as houses, trees, and other stationary items.
There are three factors of destructions from tsunamis: inundation, wave impact on structures, and erosion. Strong, tsunami-induced currents lead to the erosion of foundations and the collapse of bridges and seawalls. Flotation and drag forces move houses and overturn railroad cars.