1. Many of the world's iconic volcanoes are stratovolcanoes, characterized by their steep, conical shape. What name, which might remind you of a medieval knight's protective gear, is given to another, less common type of volcano?
From Quiz River Deep - Mountain High
Answer:
Shield volcano
As their name implies, stratovolcanoes, or composite volcanoes, are built up by many layers of hardened lava and tephra (fragmented volcanic material), which account for their distinctive profile. This structure is due to the high viscosity of the lava, which cools and hardens quickly instead of spreading out. Shield volcanoes, on the other hand, are formed by the eruption of low-viscosity lava, which is able to travel for longer distances before cooling down in broad sheets - whose accumulation results in a low, gently sloping shape, similar to a shield lying on the ground.
While stratovolcanoes are associated with explosive activity, shield volcanoes are the product of effusive eruptions. Active shield volcanoes, such as those found in Hawaii - part of the world's largest chain of shield volcanoes, the Hawaiian-Emperor seamount chain in the Pacific Ocean - are almost constantly active. The gradual buildup of lava often creates extremely large volcanoes in terms of width: such is the case of Mauna Loa, on the island of Hawaii, which is over 100 km (60 mi) wide at its base. In addition, Mauna Loa is so massive that it depresses the crust beneath it by 8 km (5 mi) - meaning that the mountain's total height is about twice that of Mount Everest. Shield volcanoes do not only occur on Earth: Olympus Mons, the tallest known mountain in the Solar System, is a shield volcano.
Other forms of volcanic mountains are cinder cones (hills created by loose pyroclastic fragments around volcanic vents) and lava domes (mound-shaped protrusions of viscous lava). The term "shield volcano" is a literal translation of the German "Schildvulkan", coined by Austrian geologist Eduard Suess in 1888.
This burning question was written by LadyNym of the Phoenix Rising team.