Final answer:
A maar volcano is a volcanic crater formed by a steam explosion due to molten rock and water interaction. Example of a maar volcano is the Hole in the Ground in Oregon. Other examples of volcanoes include Mauna Loa and Mount Shasta.
Step-by-step explanation:
A maar volcano is a type of volcanic crater that is formed when molten rock comes into contact with groundwater or surface water. The intense heat causes a rapid steam explosion, creating a shallow, wide crater with steep walls. An example of a maar volcano is the Hole in the Ground in Oregon.
In contrast, Mauna Loa in Hawaii is a shield volcano, which is a type of volcano that has a broad, gentle slope and is formed by successive layers of basaltic lava flows. Mount Shasta in California is a stratovolcano, characterized by a conical shape and steep sides due to alternating layers of lava, ash, and other volcanic materials.