Effusive eruption from effusive to explosive, due to pressure build up below the lava dome. Effusive eruption An effusive eruption is a type of volcanic eruption in which lava steadily flows out of a volcano onto the ground. There are two major groupings of eruptions: effusive and explosive. Effusive eruption differs from explosive eruption, wherein magma is violently fragmented and rapidly expelled from a volcano. Effusive eruptions are most common in basaltic magmas, but they also occur in intermediate and felsic magmas. These eruptions form lava flows and lava domes, each of which vary in shape, length, and width. Deep in the
Lava bear Alfred Bayne. As late as 1981, scientist were being asked to identify small bear tracks in the Fort Rock area to determine if they were made by lava bears. Today, it is accepted that lava bears are actually common American black bears. It is also generally acknowledged that all of the animals that were killed or captured between 1917 and 1934 were either black bear cubs or small adults stunted from malnutrition. In 1924, Bend Senior High School selected the lava bear as the school’s sports mascot. The mascot was chosen shortly after a living bear was exhibited in Bend.