Lava Flows

Lava Flows

Viscosity Viscosity means the thickness of a liquid

Viscous lava is thick and gooey and does not travel very fast or very far Lava with HIGH SILICA CONTENT is viscous

Non-viscous lava is watery and travels fast and far Lava with LOW SILICA CONTENT is non-viscous

What Erupts from a Volcano?

Lava can be thick or

thin.

Blocky lava

PahoehoeAa Pillow lava

The viscosity (thickness) of the

lava determines the type of volcano

Shield Volcanoes

Low Silica = non-viscous Low Gases = not very explosive Erupts constantly but is usually harmless

Cinder Cone

Low Silica = non-viscous High Gases = explosive Erupts often but is not usually dangerous

Composite Volcano

High Silica: Viscous High Gases: Explosive Erupts rarely but can be very dramatic and

violent

Pyroclastic Flows Very dense flow of hot ash, rock fragments,

and hot gases. Pyroclastic flow move along the ground and

in the air. They ride on a cushion of air and can travel up to 200 mph.

They destroy everything in their path and can carry volcanic ash hundreds of miles

What Erupts from a Volcano?Pyroclastic material• Rock fragments created by eruptions

• magma explodes from volcano and solidifies in the air

• existing rock is shattered by powerful eruptions

Volcanic blocks

Volcanic bombs

Lapilli

Volcanic ash

Lahars

Lahars are avalanches of mud created when hot lava melts snow and ice

They can be incredibly powerful and totally destroy whatever is in their way

Pair and Share Turn to the person next to you and discuss

how a lahar might be more damaging than a lava flow.

Geothermal Energy

Geothermal Energy Geothermal energy has been used for

thousands of years as hot springs and to heat pools.

It is a clean, renewable source of energy. Unlike wind and solar, it is very reliable.

There are only 77 geothermal power plants in the US, producing only a tiny fraction of our electricity.

However, geothermal energy could produce more than 20% of our nation’s energy. Almost all of it would come from the West, and Colorado.

Exit Ticket 1. What does viscosity mean?

2. Which type of volcano has the most viscous lava? Why does this make it deadly?