1) There are several types of plate boundaries including convergent boundaries where plates collide and form mountains, divergent boundaries where plates separate and form rift valleys, and transform boundaries where plates slide past each other causing earthquakes. 2) Earthquakes occur when rocks underground suddenly break along a fault line. Major earthquakes can cause extensive damage to infrastructure and loss of life. They also sometimes trigger tsunamis. 3) Tsunamis are large sea waves caused by earthquakes or other seismic events under the sea. The 2011 tsunami in Japan was triggered by a powerful earthquake and resulted in over 3,000 deaths as well as nuclear radiation leaks.