A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form.
Mauna Loa, a shield volcano in Hawaii
An Ancient Greek warrior's shield—its circular shape and gently sloping surface, with a central raised area, is a shape shared by many shield volcanoes.
ʻAʻa advances over solidified pāhoehoe on Kīlauea, Hawaiʻi
A pāhoehoe lava fountain on Kīlauea erupts
A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilometres long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava tubes. After some time, the eruption tends to become focused at one or more spatter cones. Small fissure vents may not be easily discernible from the air, but the crater rows or the canyons built up by some of them are.
A volcanic fissure and lava channel
Eruption fissure with spatter cones, Holuhraun, Iceland, 2014
Mauna Loa with different lava flows and fissure vent