Mount Pinatubo is an active stratovolcano, or a cone-shaped volcano, that is made from many layers of hardened ash, lava and other volcanic rock. Stratovolcanoes are also called composite volcanoes.
According to Live Science, stratovolcanoes are capable of extremely violent and abrupt eruptions in which tons of hot lava and ash are ejected. Mount Pinatubo is famous for the second-largest eruption in the 20th century, which occurred in 1991. The famous eruption resulted in over 10 billion tons of lava and 20 million tons of toxic sulfur dioxide covering the surrounding area. More than 60,000 people needed to be evacuated.