By Ethan Banks

11/03/2010

Volcanoes

Volcanoes for dummies

A shield volcano is a broad, gently sloping, volcano where gently flowing lava hardens and gradually builds up.

This is the shield volcano Mauna Loa in Hawaii.

Shield Volcanoes

Side vent

crater

Main chamber Lava flow

Composite Volcano

Layers of lava alternate ash, cinders, and bombs, to make up a composite volcano

which has both quiet and explosive eruptions.

Layer of ash layers of

lava

Central ventcrater

Cinder Cone VolcanoWhen cinders erupt explosively from a volcano vent,

they pile up around the vent creating a cone shaped hill called a cinder cone volcano.

layers of cinders

crater

Main vent

cinders

CalderaA caldera is a volcano that has blown all of its contents becomes a hollow shell. One of the biggest calderas is

Crater Lake in Oregon.

extinct magma chamber

Lake in old craterBlown off top

Hot Springs and GeysersA hot spring is where ground-water has been heated

inside a pool. A geyser is where water trapped underground sprays from underground. The most

famous geyser is “Old Faithful” in Yellowstone Nat. Parkspray of water

Lava pipePool of water

Lava touching waterUnderground

pool

Extra, extra, extra!Did you know that there are two different kinds of

lava? The two kinds are, Pahoehoe ( pah hoh ee hoh ee ) and aa (ah ah). Pahoehoe is a runny, thin lava that

flows easily. Aa is cooler, slow moving lava that hardens into huge chunks.

Pahoehoe volcano

Cooled Pahoehoe

Moving Pahoehoe

Cooled aa

Moving aa

Aa volcano