Their magma originates in the upper mantle or the lower crust and varies in composition . Volcanoes come in all shapes and sizes. The more common types are shield volcanoes, stratovolcanoes, and cinder cones. Shield volcanoes gained their name from the fact that their profile against the horizon looks like a shield laying on the ground. The flanks of a shield volcano have low slopes, sometimes only a few degrees from horizontal.
Shield volcanoes are the largest volcanic features on earth.
The largest shield volcano, Mauna Loa in the Hawaiian Islands, has a volume 300 times greater than that of the largest stratovolcano, Mount Fuji in Japan. Shield volcanoes are created through the eruption of basaltic magmas , which flow easily and thus are capable of flowing over the landscape many miles from the central fissures or vents. Photo of Mauna Loa, a shield volcano in Hawaii Stratovolcanoes are volcanoes that consists of intermixed layers of lava flows and poorly consolidated volcanic material such as ash and cinders . Photo of Mt. Hood in Oregon, a stratovolcano that has been somewhat eroded by glacial activity. They cool down as they shoot through the air, and fall back down as solid particles.