Shield volcano are cave-like volcanic straights formed by the hardening of overlaying lava. These structures help further the propagation of lava, as the walls of the tube insulates the lava within. Lava tubes can account for a large portion of shield volcano activity; for example, an estimated 58% of the lava forming Kīlauea comes from lava tubes. In some shield volcano eruptions, basaltic lava pours out of a long fissure instead of a central vent, and shrouds the countryside with a long band of volcanic material in the form of a broad plateau. Plateaus of this type exist in Iceland, Washington, Oregon,
Solfatara (volcano) Solfatara (volcano) Solfatara () is a shallow volcanic crater at Pozzuoli, near Naples, part of the Phlegraean Fields () volcanic area. It is a dormant volcano, which still emits jets of steam with sulfurous fumes. The name comes from the Latin, "Sulpha terra", "land of sulfur", or "sulfur earth". It was formed around 4000 years ago and last erupted in 1198 with what was probably a "phreatic" eruption - an explosive steam-driven eruption caused when groundwater interacts with magma. The crater floor is a popular tourist attraction, as it has many fumaroles and mud pools. The area is well known