Lava Flows
Feb 24, 2016
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?