Volcanoes

Front

Water vapor and other gases trapped in magma creates

Back

pressure

Front

More iron (Fe) and magnesium (Mg) makes magma

Back

thinner and more fluid-like

Front

Where can volcanoes form?

Back

hot spots and plate boundaries

Front

What characteristic is most important in determining how a volcano will erupt?

Back

Silica content

Front

Unlike pahoehoe lava, A'a lava is

Back

blockier, jagged, silica-rich, and generally slower moving

Front

Magma when it reaches the Earth's surface

Back

lava

Front

Lava that contains large amounts of silica

Back

tends to be thicker and more viscous

Front

How were flood basalts in the Pacific Northwest of the US formed?

Back

Fissure eruptions with high Fe and Mg contents

Front

viscosity

Back

the resistance to flow of a fluid

Front

When plates collide, the more dense plate _____ below the less dense plate.

Back

subducts