Volcanic Landforms 6 th Grade
2 Kinds of Volcanic Eruptions Quiet Eruptions: – If magma is low in silica – Lava is low in viscosity and flows easily Explosive Eruptions: – If magma is high in silica – Lava is high in viscosity and flows slowly – Explosive eruptions breaks lava into fragments that quickly cool and harden into pieces of different sizes like ash, cinders, bombs in a pyroclastic flow
Pyroclastic Flow: when an explosive eruption hurls out a mixture of hot gases, ash, cinders, and bombs Ash: fine, rocky particles as small as a speck of dust Cinders: pebble-sized particles Bombs: large particles that range from the size of a baseball to the size of a car
Volcanic Ash Cloud GLXecQ GLXecQ
Volcanic Eruptions create landforms made of lava, ash, and other materials. 4 Types of Landforms: 1) Shield Volcanoes 2) Cinder Cone Volcanoes 3) Composite Volcanoes 4) Lava Plateaus
Types of Volcanoes: Composite, Cinder Cone, and Shield
Shield Volcano
Shield Volcanoes
Shield Volcano
Shield Volcanoes
Characteristics of a Shield Volcano A short, but wide, broad volcano (can be as much as 4 miles wide!) Caused by thin layers of basaltic lava with low viscosity Caused by quiet eruptions has a caldera (large, cauldron-shaped crater) on top Hawaiian Islands are made up of shield volcanoes (including Mt. Kilauea and Mouna Loa –2 of the most active volcanoes in the world!) Very little pyroclastic material
Cinder Cone Volcanoes
A volcano with a steep slope and a large crater Lava has a high viscosity Ex. Paricutin in Mexico built up a cinder cone 400 meters high
Composite Volcanoes
Tall volcanoes with small craters Alternate between quiet eruptions and explosive eruptions ex. Mount St. Helens in Washington State and Mount Fuji in Japan