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Types of Fronts Volcanoes Have

Volcanoes have a very important function on Earth's ecosystem. They exemplify one of nature's greatest phenomenons, which can be an overwhelmingly destructive force, causing major negative impacts on the environment, and at the same time they can be a source of renewal and regeneration. Scientists classify volcanoes according to their types and characteristics, since volcanoes can show many different fronts that distinguish them from others.

  1. Cinder Cone Volcanoes

    • Cinder cone volcanoes are among the simplest volcanoes to understand. They commonly have a large, single vent, which allows molten rock material and congealed lava to escape high into the atmosphere. Tremendous interior gas pressures blow the lava material vertically into the air, where it fragments into smaller particles. When the smaller particles drift back down, they solidify and transform into cinders. Over a long period of time, the cinders form an oval or round cone-shaped base. Nearly all cinder cone volcanoes have a bowl-like depression at their summit, and their sides or flanks appear quite symmetrical and steep. Cinder cone volcanoes appear commonly in western North America, and usually do not exceed 1,000 feet in height over their terrain.

    Composite Volcano

    • Composite volcanoes account for some of the most spectacular mountains on Earth. Often called stratovolcanoes, they have very steep sides, with large symmetrical cone bases. They have a composition consisting of many different material layers, which includes volcanic ash, lava flows, cinders, blocks and large rock bombs.They can rise 8,000 feet and more above the terrain. Some of Earth's most notable composite volcanoes include Mount Hood, Mount St. Helens, Mount Cotopaxi in Ecuador, Mount Rainier, Mount Fuji in Japan and Mount Shasta. Many composite volcanoes have a central vent that branches off into fissures, with the largest vent rising to the top of the crater or caldera. Lava typically forms inside the fissures, which act as ribs, giving the cone great structural strength.

    Shield Volcanoes

    • Shield volcanoes get their name from the profile they leave after repeated eruptions. A central vent usually expels fluid lava in all directions, building up the cone in broad, gently sloping sides. The top usually remains flat and uniform, unless multiple vents have broken the surface. They build up very slowly over time, piling accretions of fluid lava one on top of the other. The basalt lava they emit can travel great distances until it cools and solidifies in great ropelike structures or thin sheets. Some shield volcanoes have numerous vents that erupt along a rift zone (fractures), sometimes forming great walls of fire. Many shield volcanoes have diameters of three to four miles across. The Hawaiian Islands consist of an entire chain of linear shield volcanoes, which have erupted for centuries -- Kilauea and Mauna Loa being the largest and tallest examples.

    Lava Domes

    • Lava domes grow mainly by slow expansion, created by small bulblike masses of lava that do not travel for long distances. The lava piles up around the main vent, cools and then fractures. The fractured lava forms knobs or spines over the vent rim. Lava domes can protrude from the main craters and flanks of composite volcanoes, signaling a new vent that has risen to the surface. Mount St. Helens had such a lava dome on its side flank, which eventually burst, causing a lateral eruption. Some lava domes form shallow, steep-sided walls, known as "coulees."

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