A composite volcano (also known as a stratovolcano) is a volcano that is characterized by the steep slope around it. This landform (the steep slope) was built up from millions of years of eruptions; this results in an accumulation of lava and ash. The lava does not flow far down the slope but instead builds up and makes the slope larger (hence the name "composite volcano"). Composite volcanoes are characterized by their infrequent but violent eruptions. An example of a composite volcano is Mount St. Helens in Washington state.
Shield volcanoes are volcanoes that have been built up by thin lava flows over a long period of time. The predominant landform around shield volcanoes are the gentle slopes around the vent that contains the volcano. The low-lying slopes cause the lava to travel a longer distance than in composite volcanoes. Because the slope is not as built up, eruptions from shield volcanoes are not as violent as composite volcano eruptions. Famous shield volcanoes include Mauna Loa in Hawaii.
Some volcanoes are found within a landform called a crater, which is a deep, circular depression in the Earth caused by gas or, occasionally, meteor strikes. Craters are normally less than a couple of miles long; bigger forms of craters are call calderas, and calderas are often formed from the collapse of a composite or shield volcano. Famous examples of calderas are found in the Western United States, including Crater Lake Caldera in Oregon and Valles Caldera in New Mexico.
A lava dome is a type of volcano that occurs in a relatively flat surface and whose magma is especially viscous (which means that it does not flow easily). As a result, the lava builds up around the volcano and creates blocks of solid lava that eventually break off. Lava domes have a rough surface, and any slopes that surround them are generally unstable. There are several lava domes located in Chile.