Where are volcanoes found?
Volcanoes can be found all over the world but most are concentrated along plate boundaries. The majority of the world’s active volcanoes are located along convergent plate boundaries, especially around the Pacific Ocean. Most active U.S. volcanoes are located in Alaska or in the Cascade Range of Washington, Oregon, and California. Volcanoes form from magma generated by the melting of plates descending into subduction zones. • Why are there volcanoes in Hawaii? The state of Hawaii is made up almost exclusively of volcanoes yet it is not located along a plate boundary. Hawaii is located above a hot spot in the mantle. Magma rising from the hot spot forms a line of volcanoes (Hawaiian island chain) as the overlying plate passes over the hot spot. How do Hawaiian and Cascade (and Alaska) volcanoes differ? Hawaiian volcanoes differ from Alaskan and Cascade volcanoes in their shape and style of eruption. Hawaiian volcanoes have broad gently sloping sides built up from lava produced during re
Volcanoes can be found all over the world but most are concentrated along plate boundaries. The majority of the world’s active volcanoes are located along convergent plate boundaries, especially around the Pacific Ocean. Most active U.S. volcanoes are located in Alaska or in the Cascade Range of Washington, Oregon and California. Volcanoes form from magma generated by the melting of plates descending into subduction zones. • Why are there volcanoes in Hawaii? The state of Hawaii is made up almost exclusively of volcanoes yet it is not located along a plate boundary. Hawaii is located above a hot spot in the mantle. Magma rising from the hot spot forms a line of volcanoes (Hawaiian island chain) as the overlying plate passes over the hot spot. How do Hawaiian and Cascade (& Alaska) volcanoes differ? Hawaiian volcanoes differ from Alaskan and Cascade volcanoes in their shape and style of eruption. Hawaiian volcanoes have broad gently sloping sides built up from lava produced during relat
How are they formed? Do all volcanoes give off the same type of material? (Volcanoes emit lava, tephra or rock fragments, and gases; these differ according to volcano type.) • Organize students into three groups. As students watch the program, have each group take notes on one of the following areas: what scientists are trying to measure and the instruments they used, the challenges and dangers researchers faced, and past volcanic eruptions and the damage caused by each. After Watching • Have students share their notes. Make a chart on the board that includes what scientists measured, what kind of technology they used, and what they learned from their tests. (Scientists used seismographs to detect earthquake distribution, employed satellite imaging to measure changes in land deformation, took gas measurements to determine gas content and levels, and obtained lava samples to better understand the dynamics of the volcano’s magma.) Include in the discussion the challenges and dangers rese
