What defines a composite volcano?

A composite volcano, also known as a stratovolcano, is characterized by its structure, which is formed by alternating layers of lava flow and volcanic ash. This layering is a result of the different types of eruptions that occur; more viscous lava results in the creation of steep-sided cones, while explosive eruptions produce ash and debris that create a wider base. This combination of materials and eruptive styles gives composite volcanoes their distinctive shape and is a key aspect of their definition.

The other options do not accurately represent the defining features of a composite volcano. For example, stating that it is composed entirely of lava flows overlooks the significant role that ash and other volcanic materials play in its formation. Similarly, being small in size but frequently erupting does not capture the true nature of composite volcanoes, which can vary greatly in size and eruptions are typically less frequent but more powerful. Lastly, while some composite volcanoes may be found in oceanic regions, many are located on continental landmasses and do not fit exclusively into this geographic parameter.